The black ooze ate away at Snape's body, but Snape was focused on the fear that ate away at his mind. 

He tried to keep his face controlled as Lupin and Dumbledore knelt beside him on the cliff, their wands ticking against his robes.  Lupin's voice rose and fell with each tick, contributing to a healing spell. 

Black liquid slid beneath the surface of Snape's skin, a thick oil spilling into his limbs, burning and freezing each place it touched.  He pushed Lupin's wand away.   "Your spells aren't working.  If you had half a brain, you'd try Tersus-"

"I don't need you to recite the counter curses to me," Lupin's voice rose over the crashing surf.  His hands dropped to his lap.  "If you weren't such a pedantic old git-"

"Just checking your sums.  And you're the same age as I am."

"You're as ill-tempered as someone a hundred years older."

"I resent that," said Dumbledore, a smile playing on his lips, his fingers never stopping their movements. 

Lupin flushed.  "I'm sorry, Headmaster...and Severus. I don't know what came over me." 

Snape couldn't help it; he chuckled.  "Two decades of my jabs, and this is the first time you've broken that polite façade of yours."  The weight of this settled on him, and his amusement vanished.  "Clearly, I'm dying." 

Dumbledore's smile dropped.  "Rest.  Let us do what we can."

Albus was right.  He was letting his temper use up what little resources he had left, and distracting the two people who might be able to save him. 

You must rest, Mr. Snape. He'd heard a nurse say that, years ago, when his father lay dying in his hospital bed.  His father had gotten hold of the nurse's forearm, and it had taken a needleful of sedation before he'd let go.  Even then, his eyes remained wide and bloodshot, staring fixedly at Severus. 

"I won't let them take me," his father had said, his jaw snapping shut between breaths. "Don't let them take me."  The wildness left his father's eyes for a moment, and he beckoned.  "Severus..." 

Something in his father's tone gave him the courage to approach the bed.  He watched his father die, and he swore to himself: never again.  Never would he look at his father-at anything-with such terror in his eyes. 

But as Dumbledore and Lupin tried counter-spell after counter-spell, his terror rose. I won't let them take me.  Don't let them take me.  And another thought, more powerful than the darkness: don't let me die like my father.

Lily bent over their son and wrapped her cloak around him.  She had been quiet as Lupin and Dumbledore worked to save his life.  Now she gripped his hand, as if she could hold him there by force.  "Fight this," she said.

He concentrated on her strong grip, on the crashing of the waves.  He tried to ignore the terror.  "I want to find peace."

Lily's fingers dug into him. "Peace can go rot," she hissed.  "Do you think I have peace?  I could.  I could lie back and let my bloody curse run havoc in my head until I was left with less sense than a potato.  I'm not going to be at peace.  I'm going to be at war."

"You didn't see him at the end.  My father."  He and Lily had parted ways at that point.  He had pursued the Dark Arts with ever-increasing fervor, and the rift between himself and Lily fell into the jumble of thoughts he didn't examine too closely, merely wishing the constant loop of their final conversations would go away. 

He focused on developing spells.  Curses.  He had been scribbling his notes onto parchment when his mother informed him that his father was at hospital.  His first thought was that he should find Lily.  Then he realized that was an old reaction, like an amputee who still reaches out with his missing limb.  He wished that he could develop a curse to wipe out memories. 

"You didn't see him," he told Lily, fighting back a violent cough.  The curse seeped into his chest, lacerating his lungs.  "He was raging.  Not a moment's peace.  Not until after he died.  I want to find peace."

Lily's neck was taut, her eyes tracing the interlacing of their fingers.  "I'm sorry, Severus."  Her jaw hardened.  "I'm sorry, but this is a marriage.  Equal responsibility.  If I fight, you fight." 

The plateau shifted underneath them, the bones of the cliff cracking and crumbling with the collapse of the cave.  Dumbledore and Lupin were thrown back, and they turned, lashing their wands toward the widening cracks, attempting to prevent the rock face from collapsing into the sea.  Lily checked the stability of the healing spells and counter-curses woven around Snape.  They were stable.  But they were simply not strong enough.

Her stiff posture broke, and she pressed her forehead into his shoulder.  "Tell me when I fell in love with you.  Tell me when I knew I wanted to build a life with you."

Because soon, he would no longer be there to tell her.  Soon, he would just be a childhood memory.  Without his physical presence as a constant reminder, Rapio Memoria would wipe the rest away.  He felt guilty for arguing with her.  She didn't want to forget him, but this-like death-was inevitable. 

"I'm not certain when you decided it was love," he said.  "I think it was about the time I started changing Harry's nappies."

She smiled.  "Sounds terribly practical of me."  She looked down at Harry, her face falling.  The boy was completely still.  Empty.  "He'll come back, and he'll need you."

"Severus," Dumbledore interrupted.  We need to get you to away from here.  The cliff-"

"Headmaster," said Snape.  He could hear the strain in his own voice.  "Harry will return."

Lupin knelt by Harry's body and gently brushed the dust from his face.  "We can take him with us."

"That may prevent his soul from finding his body.  A pathway between worlds was created here.  That pathway will lead him back."

Lily nodded.  "It will lead him home."  Then her face tightened.  Nothing momentous, a slight shift.  But Snape knew what it meant.  Her cycle was drawing to a close.  She was going to forget.  And she was trying to fight it.  Before, he'd wished that she would accept it, to ease the pain.  Now he understood.  She had to fight. 

"Stay with me," he said. 

She squeezed his hand even tighter.  "Tell me...tell me when you first saw me."

But he couldn't.  It wasn't love at first sight.  He had likely passed her in the grammar school hallways, and hadn't noticed her. 

Then one clear September day, he'd looked at her and something had changed: a shift in the breeze, a certain slant of light, and every detail of her face was familiar, as though he'd known her all his life. 

Mist was swirling up from the sea, shrouding everyone on the cliff.  Lupin's voice cut through the haze.  "Lily, he can't stay here."

Lily looked at Severus.  "St. Mungo's--"

"The Dark Lord would not have used this blade if it could be easily cured by a medi-wizard."  The counter-curses had slowed its progress, but it was only a matter of time.  The Patronum Totus--and his son--were the only cure.

The faded look in Lupin and Dumbledore's eyes showed that they knew it, too. 

"He'll come," said Dumbledore.  "Have faith."  He laid out another web of spells, and the shifting plateau stilled. 

Have faith.  Any faith Snape once held had seeped from his bones long ago.  He'd sought forgiveness, he'd sought redemption, and yet he had never had enough faith to believe he could achieve either one. 

Faith in what was possible.  That's what he'd seen in Lily all those years ago.  He could see it now, although she was more hardened by experience.  She believed he could be saved. When he told her what he'd done to her, she couldn't forgive him, but she stayed with him.  Because she had faith that one day, she could forgive him.  She had more faith in him than he had in himself.

Lily features darkened.  The curse was taking her; she couldn't hold on any longer.  Neither could he.  I'm sorry, he wanted to say, but the words would not come.  All he could feel was the fading pressure of Lily's hands.  He cast about for something to keep him there, some light in the darkness. 

Like a flame erupting, he saw it: Harry's body heaved and bolted upright. 

Severus thought he didn't have any spark of life left.  But he found it now, a burst of energy as he called out: "Harry!"

Dumbledore and Lupin whirled around, echoing the shout.  But Harry was already crouched by Snape, his eyes intent.  A Patronus burst from Harry's wand and settled at Snape's side, lapping away the black ooze seeping from the wound.  The wound stung as it healed.  But it was surface healing; the curse had spread deep inside him.  Their combined Patronus was the only thing that would stop the curse. 

"Patronum Totus."  Harry's words echoed distantly.  Snape's wand had slipped from his fingers and fallen to the ground.  Harry put the wand in his hand, but Snape's fingers were too curse-numbed to grip it.  Perhaps, with Lily's help...but her eyes were compressed in knotted lines, rasps escaping her throat as she fought against her curse. 

He saw the desperate light in his son's eyes, and steeled himself for what he had to say.  "Dumbledore will get you back to Hogwarts.  You'll both be all right."  He drank his fill of his son, living and breathing again.  "You're all right."  The feel of Harry's hand was ebbing away now, but that was all right.  His son was home.  Everything was all right now. 

Harry pressed his hands to his temples.  "I'm sorry, Mum," he finally said.  "I thought I could save you, but Dad..."  he made a choking noise as he swallowed.  "I'm sorry."  He laid both palms on Snape's shoulders. 

A warmth spread from Harry's hands.  Snape looked into his son's eyes, and could feel the connection they shared through multiple Occlumency and Legilimency lessons, the effortless way they could be in each other's thoughts.  And he understood: another Snape, in another world.  A curse eater, meant for Lily. 

His thoughts sped along the track of Harry's mind, and saw the choice Harry had made.  Remove Lily's curse, or save Snape.  "You should have told me-"

"I'll use it on you.  Save you."  The indecision Snape had seen in Harry was gone. 

"Too dangerous-"

But the warmth already ran though his body, and the darkness lessened.  The curse was shriveling, scattering.  His strength came back to him.  He let Harry feel what he was feeling, and the boy used the connection, determined to find and eradicate every last bit of the curse.

And then it was gone.  He broke free of it, surfacing from murky waters.  

"Harry-" he began.

But Harry wasn't listening.  He had reached out to his mum, a feverish look in his eyes. 

Their connection still lingered.  He focused on Harry's thoughts.  Then Snape heard it: a clanging alarm, deep within Harry's mind.  It took him another moment sifting through his son's memories to understand:  wards, keeping Harry from harm.  To stop him when the energy of the curse eater had been used up.  To keep Harry from absorbing Lily's curse himself. 

Harry was breaking past those wards. 

Snape grabbed his shoulder, shaking him, but Harry's focus on Lily was a power of its own. 

"Harry.  You need to stop."

"Can't."

"You will.  You cannot allow yourself to become cursed."  Snape tried to wrest Harry away from Lily, but the boy's grip was something beyond sheer physical force.  His stomach roiled.  This curse-his curse-inside his son...

"If I need to hex you, I will," he said.  "Let go."

"Last chance.  Only chance."  The echoing of Harry's voice, that ghostly quality to his thoughts-it was still there.  Snape had thought the curse was dulling his senses, but now he wondered. 

"Harry.  Which Harry are you?"

Harry looked at him.  Snape could see it: two boys through one set of eyes.  Harry Potter hadn't made it back to his side.  He was right here, with his son.  Two souls in one body. 

"We can cure her.  Let me do this."  It was clear from Harry's tone that it wasn't about letting at all; he was going to do this, regardless. 

Dumbledore and Lupin lost ground as the cliff, inch by inch, fell into the sea.  Chaos.  It never went away.  Why couldn't he stop things from falling apart? 

"Harry.  Please." Snape wrenched the boy's face toward him.  Their mental connection was still there.  Perhaps if he could draw Harry into his mind, he could cut him off from Lily.  Separate him mentally if he could not do so physically. 

It was a delicate operation.  Legilimency was meant for invading another's thoughts, not pulling someone else's mind into your own.  He had read about using Legilimency in this way, but had never attempted it.  With anyone else, he would not have tried.  But he knew the pathways of his son's mind.  And he only had moments to stop what was happening.  

He pulled at Harry's thoughts, drawing him in, and had the curious sensation of falling into himself.  The world shifted, and it was just the two of them, surrounded by shadows.  They were safe within the walls of Snape's mind.  A chance to be alone, and to talk.

But they weren't alone.  Voices muttered and rose as a memory coalesced around them.  Snape pushed deeper, to find a quiet corner of his mind.  But the memory fell solidly into place, white hospital walls rising up around them. 

His father lay in the bed, beckoning.   A young Severus stood nearby. 

Over the beeping of the hospital machines, Snape heard something else, something that wasn't part of the memory: scratching, scuttling. 

Harry looked around.  "Where--?"

"Shh," said Snape.  He pressed his ear against the wall.  Tiny claws scratched, closer now.  He wanted to say it wasn't real.  But with magic, anything could be real, and dangerous. 

Harry leaned against the wall and the scratching got louder, more frantic, mandibles tearing through plaster and wood. 

Snape pulled Harry away. 

"It's after me," Harry said.

It's not real, Snape wanted to say.  But it was real.  He'd made it real.  "It's a manifestation of the curse.  It's trying to find you."

"It's okay," said Harry, and he smiled.  "I'm ready.  It's my chance to do something other than watch and wait."

"I want you to stop.  Your mum would want you to stop, too."

Harry's smile faltered.  "Can't you hear it?  You talk about her like she's not really there.  Like she's already dead." 

"Harry, this isn't the time.  I know about the curse eater.  I knew about such things when I developed the Rapio Memoria.  I prepared for them.   Do you understand?" 

Awareness spread across Harry's face, followed by disappointment.  "It won't work.  She'll still be cursed."

Bless the boy for thinking the young, Death Eater Snape had been that benign.  "More than that.  It will attack you.  You must stop now.  All you will accomplish is cursing yourself."

Harry shook his head.  "I can feel it working.  She's getting better.  Light filled Harry's face.  "I can do something for her.  Finally." 

A sudden shift of light, or some inflection of Harry's voice, and Snape knew.  It  wasn't Harry Potter that he needed to convince.  It wasn't Harry Potter exerting influence over his son as they shared this one body.  Snape had attributed Harry's actions to the stubborn child of that other world.  The boy had changed while he was here, but...

It appeared his son had changed as well. 

"What's come over you?" he demanded, using the tone that had always garnered obedience in the past.  "Stop this at once."

The fear that had been nibbling at the corners of Snape's mind could no longer be avoided when he saw the glint in Harry's eyes.  "I'm sorry, Dad, but I can't.  All my life, I've wanted to do this.  I shouldn't have promised.  I've never broken a promise in my life.  But once I saw her again..."  His voice grew soft.  "Some promises are older than others.  Ones I've made to myself.  To mum."  Harry looked away from Snape.  "I should have tried to make you understand."

Promises to her.  Snape understood those.  He should have known it would be in his son as well, amplified by thirteen years of watching and hoping. 

He had convinced himself that he had been a sufficient buffer between mother and son. He'd put rules in place, tried to control the situation.  But he'd learned when he was young that control was a tricky thing.    

His younger self was still by his father's bed.  His father gripped the tubes surrounding him in one hand, breathing heavily.  The young Severus was all rigid lines, staring down at the stranger on the bed.

His father laughed.  "'Begone, old man.'  That's what you're thinking.  I don't need any of your magic to see that."

Snape couldn't hear his younger self reply.  His low voice was obscured by the rustling of little claws, seeking out whoever had tried to break Lily's curse.  Little defenders designed by a methodical young man. 

"Why?" he whispered to that younger self, someone who couldn't hear him, would never hear him.  His thinner, smaller body was bent, as if waiting for a storm to subside.  A boy, barely a man, who wanted to unleash his own curse on the world. "Why couldn't you leave it alone?"

"I won't let it take me.  I won't!" said his father.  By the time the echo of the shout faded from the room, he was dead. 

It took a moment for the younger Severus to realize it.  He stood with hands still clenched, until the medical staff rushed into the room, assaulting the body with machines and syringes. 

"Don't," the young Severus said, his eyes widening.  "Don't-don't leave me!"  I-"

I was wrong.  I'm not ready for this.  I thought I was in control.

Too late.  The heart monitor bled out its flat line.

Severus could feel all the terror he'd felt in that moment, watching his father fade away.  He'd hated the man, but his father's rages had been the clear borders to his world.  He understood what his life was with his father in it.  

But Harry was more than a border to his world.  He was everything.  And now his son was waiting for the curse to take him.  All his attempts at rules, at control, and he was still as helpless as he was twenty years ago. 

Part of the wall crumbled, and a dark insect emerged, its antennae circling toward Harry.

The iron control Snape always kept on himself, the lens through which he focused and filtered his emotions-he let it shatter.  He grabbed Harry awkwardly, desperately.   

"Harry, you can't do this because...I need you."  His voice was too loud, too high.  He was shaking.

Harry's eyes widened.  "It'll be all right.  Mum will be better.  Everything will be better." 

"It won't.  Don't you understand?"  Barely able to breathe, he choked over his words. He was terrified of himself, but he couldn't stop.  "I can't do this without you.  Any of it."

The insects streamed out of the wall, surrounding them in a chattering swarm.  He pulled the boy closer, hid his face over Harry's shoulder.  His son depended on him to be strong, but he didn't have any strength left.  "I'm sorry," he whispered.  "I'll take care of things.  I'll find a way." 

"No," said Harry.  We'll find a way.  Both of us."  He breathed out, and a warm mist filled the room.  "I'm letting go now.  Stopping."  The chattering of the insects abated.

The memory was breaking apart, and they were pulled out of it.  The room dissipated in the mist.  They were back on the cliff, the wind whipping around them.  Harry had his hands on Lily's shoulders, but he was looking at Snape.  

A thread of their mental connection remained.  Snape could still hear the whisper of his son's thoughts, and the echoing quality of Harry Potter's thoughts among them. But he also heard something else: the clacking of insects.  The curse had already gained entry into Harry's mind. 

"No," said Snape.  Rapio Memoria was powerful.  Once it gained a foothold, it had the advantage.  Snape grabbed his wand and began a series of counter-curses. 

"S'alright," said Harry, gasping. 

"Be still," said Snape, his voice quavering.  He was loosing control again.  "I need to work.  The curse is inside you."

"But it's not inside him.  Not yet.  I can take it with me."   Harry reached up and held Snape tightly.  "It's the least I can do."

"Take it with you..."  said Snape, frowning.  Then he understood: Harry Potter was talking to him.  Harry Potter was going to take the curse with him.  To save the other Harry. 

Snape dropped his wand.  "Don't!" he shouted. 

It was too late.  A light flashed, and another image of Harry appeared, a ghostly double-image.  The other Harry: half in this world, half in the in-between space that separated worlds.  A dark smog swam from Lily's body and into that misty double: the curse.  His young face contracted in pain, and the ghostly image of Harry Potter faded. 

"What happened?" Harry-the solid Harry-said, holding his head. 

Snape pulled Harry away from Lily, checking him over with his wand.  No more sign of the curse eater.  No sign of Harry Potter.  Just one Harry.  His Harry. 

"The curse.  Do you-"  He stopped.  But he had to know.  "Do you remember who I am?"

Harry looked up at him.  "Yeah.  Who could forget that face?"  He gave him a smile, but it faded.  "The other Harry.  He was in my head, we both were-"  He stopped, his face contracting.  "He was cursed, wasn't he?  I tried to pull away, but I couldn't in time, and then it was like he was all around me, blocking me...shielding me..." 

Lily opened her eyes, seeing Harry for the first time.  Harry smiled wanly at her, and Snape's suspicions were confirmed, now that he was willing to see it.  The love in Harry's eyes, the hope, but quickly followed by subdued resignation.  He knew she would not remember him. 

The darkness faded from Lily's face.  "Monkey?" Lily whispered.  She looked at Harry without hesitation, without the look of someone encountering a stranger. She looked at him the way a mother looks at her son. 

The curse was still there.  Snape could see it in the shadows of her eyes, whispering in her mind.  There had not been enough energy left to remove it completely.  It was a slight improvement, a small thing.  To anyone else, the change in her expression was nothing, the trick of a certain slant of light. 

But Harry's eyes showed that a certain slant of light was the entire world. 

Severus held them both tightly.  One small thing to hold against the chaos.  One small thing that gave him hope for a day when Lily could be whole, and he could be saved. 

The earth shifted, and someone cried out.   Lupin fell into a widening crevice.  He struggled to pull himself out.

Lily, still orienting herself, had enough presence of mind to take in the situation.  "We need to go."  

Harry pulled his eyes away from her, and looked up at Snape.  "Did he do this?  The other Harry?  Is he cursed now?"

"I don't know if it can cross over to another world.  But the curse is insidious."

Harry shook his head.  "I shouldn't have let him do it."

"I'm beginning to learn that you can't control what people do.  You can only do what you can for them, and hope the damage isn't too great."  He laid his palm on his son's head and smoothed out his hair, feeling the softness of each strand.  It never did any good; the hair stuck up anyway.  But that was all right.  His thoughts strayed to a place far from there, to another young man who had so very little, and had still given up so much. 

"Thank you, my son," he murmured.  

Dumbledore levitated Lupin from the crevice, and the two reached them in a few quick strides.  Lupin put his arms around Harry slowly, as if afraid he might disappear.  Dumbledore gripped Snape by the arm, more firmly than necessary, and beamed at Harry.  "Glad to have you back, my boy," he said, then met Snape's eye, a familiar gentleness in his features.  "Both my boys.  Welcome home."   

Harry drew in his breath.  "Home."

They backed up to the collapsed cave entrance, as rocks tumbled down into the sea. 

Let it fall apart.  Snape knew he couldn't stop it.  But right now, in this moment, he didn't need to.

"Home," repeated Severus.  In a flash of light, they were gone.