The hot water thrummed against his skin.

It felt luxurious; he couldn't remember a moment in the last week when he'd had time for more than a cleaning spell. He closed his eyes and breathed deeply. His mind drifted. The image of his son floated before him. Harry was struggling to say something. But behind his eyes, there was only emptiness. Miles and miles of emptiness.

With a great, gulping breath, Snape jerked forward and opened his eyes. He'd fallen asleep standing up, in the shower. He grabbed the soap and scrubbed furiously until his skin burned red.

He finished his shower and dressed, resisting the urge to lean over the books by his bedside. He spent his free time scouring texts for any reference to other worlds. What little he'd found had been vague and contradictory.

Kneeling by the bed, he checked on Lily. She was in a deep sleep, her hair falling away from her in soft drifts. And when she woke, she would be herself again. Or as much like herself as she ever could be.

In the past few days, Lily's gradual, month-long deterioration had reached its lowest point. She required constant care and attention. The castle House Elves helped, but they were no substitute for his own presence.

Last night, he'd worked until the predawn hours to brew the Restituomens potion for Lily. It was the best treatment he'd found, but the price he paid was watching its effectiveness gradually seep away over the month. Any more than a monthly dose was damaging. It was also intricate, and a fresh brew was required for each dose.

It shouldn't have taken so long this time. He'd dealt with the complexities of the procedure so many times that usually, only two attempts were needed before he had success. But last night, in his exhaustion, he kept making careless mistakes.

There were moments when he doubted his decision to keep the other Harry away. He'd forgotten how difficult it was to get through these days unaided. But he could trust his own son. As soon as Harry was old enough to understand, he'd been an invaluable support during Lily's dark times. Once, when Harry wasn't more than five years old, he'd come to Snape clutching a handful of photographs, asking, "will this help her, Daddy?"

The memory sliced through him like a deep wound. His breath hitched. But he was not going to fall apart. Not today.

His bones ached with fatigue. He grabbed a vial of Invigoration and swallowed it down. Then he set to packing their things.

It wasn't long before he felt teasing hands cover his eyes.

Some of the tension in his shoulders melted away. "Careful," he said, trying to sound stern. "I might accidentally pack you away."

"Oh, you'd never do that," said Lily, dropping her hands and giving him a hug from behind. "I'd wrinkle all the clothes."

"Today's the last day of term," he said, helping her orient herself.

"I guessed as much," she passed the packed bags and dropped onto the couch, her feet dangling over the side. "That, or you're leaving me for another woman."

"Never," he said, softly whacking the bottom of her sock-covered foot.

"I don't know," she said, tapping a finger to her lips. "That Minerva McGonagall can be quite the harlot."

"I'll try to resist her lewd advances."

She threw a pillow at him, which he levitated away. "Try?" she said in mock outrage.

"I'm only human."

She giggled and reached up to grab his hands, pulling him onto the couch on top of her.

He did his best to land gently and dropped his head to hers, covering her face in kisses.

Her giggles subsided and she curled her arms around his neck. Her breath was warm against his lips. "By the way," she said. "It's extremely unsatisfying to throw a pillow at you, only to watch it float gently away."

"I should let you pummel me?"

"I'm not saying you need to get a concussion. But a few soft whacks would really improve my disposition."

"You're too good to me."

She laughed again, a deep belly laugh that turned his insides to butter. "Well, there's always the making up afterward." She kissed him again, soft and slow.

He had planned to go over the morning's agenda with her once she woke. Make sure everything was set and orderly. Lily had a way of making his plans crumple like wet tissue paper.

"You know," she said thoughtfully as he held her close, "I've been thinking about pillows. The word just doesn't sound soft enough, does it?"

He smiled into her neck. He loved this game. "What should they be called, then?"

"Flufflepods. Definitely. Nobody could resist resting their head on a flufflepod. And beds? There's got to be a better name. How about it?"

He searched his mind. "Er…somnolocus?"

She pulled her head away to stare at him. "That's terrible."

"You're the naming expert."

"True." She hummed with pleasure. "People should hand their children over to me for naming. If I had a baby, I'd name him…" Her eyes unfocused, and she gave a slight gasp, as if seeing something from far away.

He pulled away to study her. He clutched her hand, mentally willing her to remember the tiny baby she'd held in her arms so many years ago.

But her eyes centered back on him and she gave an apologetic smile. "I think I wandered off there for a bit."

He nodded, burying his disappointment. "We should check on Harry," he said carefully.

Her face went blank for a moment, and then she brightened. "Our son! Coming home with us today. Just let me find my shoes and we'll go." She hopped off the couch dashed into the bedroom.

He stood patiently, waiting. She would remember Harry for the rest of the day, of course, but he'd hoped that this would be the time that she'd remember him on her own, without prompting. Still, her grasping at the memory was a good sign. He wanted to tell Harry. It would have been a small gift for him on Restituomens Day, or Rest Day, as his son liked to call it. The first day of the month when the potion was working at full strength: no lapses of forgetfulness for an entire 24 hours.

But only his own son would understand Lily's little steps forward. And his Harry wasn't here to enjoy it. He was trapped in a world where his mother was a cold memory. Snape shook his head. There was nothing he could do for his son at the moment. And he had another boy to take care of.

He asked Lily to go on without him to meet Harry in the Gryffindor common room. He felt a pang of anxiety as she strode away from him, but it was something he was used to. She spent much of her time on her own at the school, as event planner and unofficial morale officer. She worked hard to carve out a niche for herself at Hogwarts, keeping copious notes and working with students to manage her duties.

Snape half-heartedly wished she didn't manage it so well, as she tended to conspire with the Weasley twins to create extremely loud and obnoxious Gryffindor banners for any event that celebrated her own House. However, he got no sympathy from Lily, who gave him cheeky comments about Slytherin, nor from Dumbledore, who gave him lectures on the importance of morale in dark times.

He had a final meeting with Dumbledore, in the futile hope that the headmaster had discovered a way between realities in the four days since their last meeting. A few hours later, armed with some conduit-revealing spells to try, he followed the rush of students outside the castle gates. The boy was holding his trunk, gesturing animatedly as he talked with Lily.

Snape approached cautiously. The boy's face was calm and smiling. He was also getting on well with Lily, and Snape was unwilling to disrupt that.

"Ron and I are talking again," he said as Snape approached, apparently forgetting his usual animosity towards the man in the moment. "He told me we could share a compartment on the trip back to King's Cross Station. I think we'll be mates again soon." He spoke as though the two of them had parted over a disagreement, rather than been near-strangers for the past three years.

"We usually take the floo network home," Snape said gently. "It's not as though we need to meet up at King's Cross."

Harry's face fell. "Oh. Right." He gazed back at a cluster of students, where Hermione and Ron who were chatting and laughing. Then he looked at Lily, his eyes troubled. The boy was clearly torn. "It's just that Ron was there before I had…anybody," he said. "He was my best mate."

Snape was surprised by the boy's reluctance. Harry had never wanted to miss Rest Day with Lily, and had even resorted to cutting class before Snape finally started excusing him for that day each month. This would be the first Rest Day his son wouldn't spend with Lily.

And this boy stood there, thinking about lost friendships, with no understanding. He told himself that what had happened wasn't this boy's fault. He told himself that once the knew the rhythms and rules of their household, things would be better. The words echoed in his head like hollow shells.

"Your mum's doing well today," he explained to Harry. "It's a good day to spend with her."

"Oh, I don't know, Sev," she said, hunkering down to look Harry in the eye. "The Hogwarts Express is such a big part of going to school here. If he wants to go…" she shrugged. "One of us could pick him up at the station."

Snape sighed, and had been about to agree when the boy said, "Yeah, I'll do that."

He uttered a short bark of disbelief. "I beg your pardon?" Snape asked him.

The first flickerings of anger appeared. "What?"

"I did not hear a request for permission."

He watched the storm clouds gather in the boy's eyes. "I don't need your permission."

Lily stood up and crossed her arms. "You know, I can give permission, too. You're not the only parent here."

He clicked his tongue impatiently. "I'm aware of that. The point is that he didn't ask at all."

"But I don't mind if he takes the train."

"It's not about you minding. It's about learning the proper way—"

Lily threw up her hands in exasperation and stalked off toward a group of teachers. No doubt to talk their ears off about how impossible he could be. He turned back to Harry. "I'm still waiting."

Harry had the appearance of someone under the influence of Petrificus Totalus.

"Your word…"

Harry took a deep breath. "May I," he began slowly, "ride the Hogwarts Express to London?"

"Sir," prodded Snape. He was going to work the boy into shape if it was the last thing he did.

"Sir," repeated Harry, sounding as though he were grinding glass.

"You may," said Snape, trying to keep the self-satisfaction out of his voice. "I shall meet you at the station, and we'll Apparate home from there."

Harry nodded and walked stiffly towards his mum to say goodbye.

Snape ran a hand through his hair. The boy's capacity for rebellion astounded him. He'd certainly resented—even hated--his own father at that age, but following rules and asking permission were a part of daily life. In fact, they were a part of his daily life even now. He wasn't above bending the rules—he was Slytherin, after all—but he didn't know how to explain that obedience to rules was vital, especially when it came to rules about Lily.

He was overwhelmed by the same helplessness he felt when his son was nearly two years old and throwing tantrums on the kitchen floor. He cringed at the memory even now, thinking of how Lily had stared blankly into space while he kneeled over the screaming child, shouting, "Stop crying! Stop at once!" Well. He had survived his early disastrous attempts at parenting. It looked like he would have to start over again.

Harry boarded a carriage for Hogsmeade station. His eyes fixed on Lily as the carriages pulled away. Then he shifted and raised a hand toward Snape, as if to call out a question. One look at Harry's face made it clear: he was having second thoughts. But just as quickly, he snatched his hand back. Then the carriages turned a corner and disappeared from sight.

Snape was seized by the sudden, irrational urge to run after the carriages. He reminded himself that the boy would be perfectly safe on the Hogwarts Express. He let out a deep breath and walked toward Lily. He would talk to her about presenting a united face for Harry. He'd talk to her about it hourly, if necessary. He fought enough battles each day without fighting a war on two fronts in his own home.

He reached Lily and gave her hand a quick squeeze, begging understanding with his eyes. Her annoyance softened. He realized that it had been a long time since they'd been alone together on Rest Day. And he'd learned from Lily to seize moments of happiness whenever you found them.

* * *

Hours later, he stood at Platform Nine and Three-Quarters as the Hogwarts Express pulled in. The students poured out into the waiting arms of their parents. He saw Lucius Malfoy and nodded cordially, careful to keep his face neutral. He'd grown to despise the man, but needs must. Draco stepped off the train and exchanged formal greetings with Lucius. Lucius scanned the remaining passengers hungrily.

Snape felt a prickling of irritation and fear. When he'd married Lily and adopted Harry, he'd walked a fine line, implying to his former Death Eater companions that each move was made for strategic value. Lucius had slowly come to agree, and the alliance Snape had formed with Lucius had prevented any Death Eaters from attacking Harry. But for years Malfoy had also tried to acquire Harry himself, plying Harry with gifts and Snape with monetary offers. In the past year, he had stepped up his efforts, going so far as to make frequent visits to Hogwarts. The look in his eyes when he talked about Harry made Snape's skin crawl.

Harry finally tramped onto the platform, and Snape beckoned to him. The quick greeting they exchanged made the Malfoys' reunion positively syrupy by comparison. Snape pressed his hand against the boy's back, moving him quickly away from Lucius.

Snape led Harry out of the station, slipping off his outer robes and smoothing the white button-down shirt he was wearing underneath. Despite Lily's expertise in picking out clothes, he still felt awkward in Muggle wear. But he wished to talk to Harry alone first, and a nearby Muggle park was a good place for it. He sat down on an iron-wrought bench facing the park, gesturing for Harry to join him. The boy looked uncertain, and Snape resisted the urge to yank him towards the seat. Must the child consider every order as though he were being asked to walk through fire?

"I thought we were Apparating to your place."

"Our place. We are. But there's something I need to discuss with you first." He hoped the boy had the capacity to listen despite his stubbornness.

The boy shifted uneasily. "What?"

Snape's tolerance had come to an end. "Sit. Down. Now."

Harry looked ready to argue, but closed his mouth and sat.

Snape searched himself for more reserves of patience. What he was about to explain was more important than indulging his own temper. "We have some rules in our household—"

Harry let out a sharp sigh.

"—that Harry and I both agreed to, many years ago. They have served us well. I do not expect you to follow them perfectly. There are a few times—only a few—where it is necessary to break them. And sometimes…it is too easy to slip." He frowned bitterly. "But I expect you to mind them to the best of your ability." He gazed out at the park, watching the warm summer wind lap at the leaves. "They all involve your mother."

He looked back at the boy, who was now sitting straighter. His eyes were wide and attentive. Perhaps there was hope, after all.

"The first," he said softly, "is to never say remember…"