The last sound Harry or Severus expected to hear coming from the underwater grotto was laughter and singing.  They stared at each other, stunned, before swimming inside.  Harry had his wand out, prepared to fight the kelpie for Katie's return.  Severus also had his wand out.

The cave was not very large, but it was illuminated by dozens of colorful glowing sponges that cast a soft yet bright radiance over the cave.  The light caught the tiny crystals embedded in the walls and made them glitter and sparkle wildly.  It was like being inside a diamond. 

Harry rubbed his eyes and then looked towards the back of the cave, where a low shelf was situated, filled with a thick bed of seaweed and seagrass, upon which the kelpie was lying with Katie right next to him, and the most glorious voice was coming from the kelpie's throat.  Harry had never heard such a voice in all of his life.  And his girlfriend was clapping and singing along with it.

Harry rushed forward, anxious to show that he had fulfilled the conditions of the bargain before time ran out.  "Katie! There you are!" he cried.  "All right, I've found her, water horse, now it's time to keep your end of the bargain and let her go!"

The kelpie turned, snorting softly.  "Well, well. You have actually cared enough to find her. How remarkable! I didn't think there were still mortals who could feel such devotion left in the world."

The kelpie nuzzled Katie playfully. "Look, pretty one, who's come to see you."

Katie blinked, slowly coming out of the spell the fae horse had woven with his magnificent voice.  For an instant she was transported to another time and place and felt the love of a starved lonely heart.  She turned her head, breathing in the salty and sweet scent of the water horse, keeping a hand wound in his mane.

Her cerulean eyes met Harry's emerald ones.

"Who . . .?" she struggled to remember those eyes, that face, everything was muddled, her head felt as if it were wrapped in cotton wool batting. 

"Katie, it's me, Harry. Don't you remember?"  He whirled angrily upon the kelpie. "You rotten bag of bones! What did you do to her?"

"Nothing. Merely sang her a few songs."

"Songs to beguile and entrance," Severus interjected sharply. "I would not call that nothing."

The kelpie turned towards the older sorcerer. He stiffened.  "You are one of Titania's court."

"I am the Heir to Prince Manor, Severus Snape," answered the Potions Master.  "The girl you kidnapped happens to be my student, as well as my son's girlfriend. She is under my protection.  My son has fulfilled your bargain, kelpie. Now keep your end of it and let Katie Bell go." He leveled his wand threateningly.  "Or suffer the consequences."

The kelpie tossed his head, seemingly unconcerned by the other's warning.  "I have kept my end of the bargain, wizard.  I am not holding her prisoner.  Now it is up to her to choose."

Harry glided forward, until he was standing about five feet from the bed of seaweed. "Katie, listen to me.  It's Harry Snape, the one who always helped you brew potions, the one who kissed you while we were flying on our brooms back from Hogsmeade. We went out to dinner and you told me if I kissed you like that again I'd need to resuscitate you. Remember how we played that match against Ravenclaw? And you scored three goals? And how you stood up to MacLaggen for me? Remember? Remember me? You know me, you belong with me. Not him.  He doesn't love you.  I do. I've come to take you home."

"I . . ." she shook her head, those eyes pierced her, such familiar emerald eyes . . .eyes that she had seen laugh and sparkle and cry, eyes that she had seen blaze with anger and widen with fear.  Eyes that she had seen glow with love and affection . . .for her.  Do you remember? Remember me?

She shut her eyes and breathed in and out.

That kiss . . .she recalled it . . .and then all at once she jerked upright.  "I remember . . .Harry, how did you find me?"

Her eyes opened and she smiled at him, a smile full of love and contentment, and she would have rushed into his arms if not for the fact that she would drown unless she touched the kelpie. 

"Uh, I had a little help . . .okay a lot of help . . ." he amended upon seeing Severus raise an eyebrow and scowl.  "From Dad.  Do you remember me?"

"Yes! I could never forget you, Harry Albus Snape. I love you!" she cried.

"And do you choose to go home to them, Lady Katherine?" asked the kelpie, a hint of sadness in his tone. 

She turned to him and stroked his head gently.  "I'm sorry, but I can't stay with you. I belong up there.  And you have to go where your heart is.  I'm sorry, but I can't be what you want.  You're beautiful and magical and I understand why your Albia loved you, but . . .my heart belongs to Harry."

The kelpie heaved a sigh that seemed to come from the depths of his being.  "I should have known.  For only true love could hold a spirit such as yours, my lady." He dipped his head to her in respect.

Harry looked from one to the other. "What are you two talking about?" He frowned at Katie. "It almost seems like . . .you feel sorry for him. Why?"

"Because . . .he didn't kidnap me to hurt me.  He kidnapped me because he was lonely and I reminded him of the girl he had loved a long time ago and lost."

Harry didn't know what to say. For the first time he began to feel sorry for the kelpie.  Sorry for the creature who had kidnapped his girlfriend! He shot a glance at his father, expecting to see him sneering and glowering at the fae shifter.

Instead he saw Severus's face soften and understanding glint in his dark eyes. "Better to have loved and lost, than to have never loved at all," he quoted softly.

The kelpie shifted, tossing his head and then climbing to his feet. He was careful to keep Katie's hand touching his shoulder.  "And what would you know, wizard? You mortals love so easily! What would you know of watching the one you love wither and fade, like a rose touched by frost? To hold her in your arms and know that you could have saved her but for . . ." he stamped his hoof upon the floor angrily.

"But for one last moment, that was a moment too late," Severus finished.  "Oh, I know plenty about loss, kelpie. Trust me on that.  When my beloved died, I thought I would never love again. My heart was broken and shattered and I swore there would be no one else ever that could mend it." He met the fae creature's eyes steadily.

The kelpie shook his head.  "So then, you know what it is like to be empty and alone and to wish to find one who could . . .perhaps . . .mend the heart that was broken.  I have searched and searched for centuries for that one . . .the one who will be to me what Albia was . . ."

"Perhaps you would do better to stop searching and kidnapping girls and just wait for love to find you." Harry suggested.  "I mean, that's what I did.  Katie and I we were in the same House and all, we even played Quidditch together, but one day I looked at her and something just . . .clicked and I started to see her as more than just my Housemate.  It was sort of like being blind and then getting your sight back."

The kelpie cocked his head.  "Do you think that as well, Lady Katherine?"

Katie nodded. "I do.  Harry was just Harry, until one day I realized that he was someone that I could love and who loved me.  It was like finding something you had lost when you never even knew it was missing."

"And the thing that was missing was the other half of your soul," the kelpie whispered.  His lip curled.  "You are young, your love is like the first blush of spring. You have yet to face the autumn and the dark of winter."

"But that does not make it any less strong," Severus said suddenly.  "Love cannot live in the unwilling heart.  They have been tested tonight and their hearts are true. And they are right, sometimes when you stop searching, love finds you.  It did for me.  After my Lily was killed, I swore never again would I lose my heart. I buried it in the grave with her.  Or so I thought. Until Sarai came.  She was supposed to be my tutor in magic and the ways of the fae, my instructor in kin-sa-dor.  She was all of that to me and she taught me one more lesson.  How to trust and love again.  Where the heart loved once it can love again. And so I have and still do."

"Sarai? You love Sarai Kinsalari Valinek? Titania's Captain of the Guard?"

"I do.  And she is likewise pledged to me." Severus answered.

The kelpie laughed.  "Ah, now there's a lass that will take some taming, no?"

"And who says I want to tame her?" snorted the professor. "I like her just the way she is."

"You are wise then, my lord.  That is true love, to accept the other for all that he or she is, good and bad.  As my Albia did for me." He was silent for a moment, his forelock falling over his eyes.  "I have shared much tonight, more than I have ever shared with anyone other than my beloved.  ‘Tis strange, but I thought I was stealing away a bride, or so I had hoped, and instead the trick was on me."

"What do you mean?" Harry asked. 

"Because instead I found something better.  I found a friend. Or three. If . . .you will have me." The kelpie shuffled his hooves uneasily.  "I assure you, I am not like my wicked cousins, I have no liking for human flesh nor wish to harm you.  I know I am sometimes selfish and impulsive, but I am also loyal and my word is my bond. And . . .I do not call any mortal, not even one who bears the blood of the fae, friend lightly."

It was rare to see one of the proud fae humbling himself so, and all of them sensed that instinctively.  All three looked at each other for several long moments, at last coming to a silent yet satisfying conclusion.

Katie looked into the kelpie's eyes and said quietly, "We would like to be your friend, except . . .we don't know what your name is."

The kelpie coughed. "Ah.  The name my mother gave me is unpronounceable to mortals.  But Albia, my fair one, called me Duncan.  She said it meant "dark warrior" in the tongue of her mother's people.  And she was the last one to ever call me that. I would be . . .honored if you would do so also."

They agreed and then Katie climbed back up on Duncan and together the kelpie and the two mermen returned to the lake's surface just as the clock in the Entrance Hall struck midnight.

Dripping wet they emerged from the water and Severus quickly charmed their clothing on before using another potion to change them back, which he summoned from his lab. 

Then they bid farewell to Duncan, who told Harry, "If ever you need me, young Snape, don't hesitate to put your hand or foot into the water and call my name. I promise I shall come and help as best I may, like a true friend."

"Thank you," Harry said, and then he reached out and patted the water horse.

"Just mind you take good care of Lady Katherine, boy," the kelpie added mischievously. "For if not, I shall be glad to take your place and give her my heart, you hear?"

Harry grinned. "Right.  That will never happen."

"Darn straight it won't," Katie said, and then she kissed him.

* * * * * *

Ten minutes later, the two apprentice potion makers found themselves standing in front of their teacher's desk, receiving a very pointed and well-deserved lecture on their folly.  Now that they were all safe and sound, Snape allowed himself to give vent to his temper, which had been simmering ever since he had found out what these two had been doing in his lab instead of brewing potions.

" . . .could have cost both of you your lives, and for what? A two-minute kiss over a cauldron? Both of you know better! Especially you, Miss Bell. You're older and less likely to get carried away by your emotions, or so I thought."

"I'm sorry, sir." Katie stared at the ground, blinking back tears.

"Dad, don't yell at her. It was my fault, I came in and started talking to her."

"Don't you tell me whom I should lecture, young man!" snapped his father. "I'm the professor, not you! And you both behaved very irresponsibly.  More like two first years than a fifth and fourth year.  Perhaps you belong back with them, learning procedure and proper etiquette while brewing again? Maybe I ought to make you repeat a few classes, since you seem to have forgotten how to behave while brewing a master level potion?"

Both of them blanched and looked horrified.

"Dad, no! Please, anything but that!" his son groaned. "I'd rather you beat me."

Severus rolled his eyes.  "Spare me the dramatics, Mr. Snape.  I have never beaten you and well you know it. My name is not Vernon." He crossed his arms over his chest.  "In lieu of that, I will ground you for the upcoming weekend, Harry Albus Snape.  You are to report here to me at seven in the morning and I will assign you chores and an essay and you will also complete any homework you have as well. Furthermore, you are to be in bed by nine o'clock every evening, and you are not to see any of your friends, including Miss Bell, during that time."

Harry knew it was useless to argue, so he simply said, "Yes, sir. I'm sorry."

Severus then looked at Katie.  "As for you, Miss Bell, you will have detention this weekend and an essay as well, and you can also re-brew that draft for me-correctly this time. One more thing, you will refrain from speaking with or otherwise interacting with Harry for the weekend.  That ought to be a sufficient reminder of what not to do while brewing. Or you may choose the alternative I mentioned before."

Katie shook her head. "No, Professor. I'd rather squish a million dungbeetles than that, sir."

Snape frowned severely at her for another ten seconds before clearing his throat.  Then he waved his wand and a table popped up inbetween them with all of the food from the feast they had missed while on their adventure beneath the lake. 

They stared at each other, mouths agape.

"Well? What are you waiting for? Sit and eat, I know you must be starving after all of that emotional upheaval."

The two sat down and began to eat, discovering that the professor was right. 

To their eternal surprise, Severus also took a plate of food and sat down at his desk to eat. 

After the children had finished their supper, a selection of sweets and cakes appeared on their plates.  They looked up at Snape's desk . . .where the professor was calmly eating a slice of pumpkin pie. 

Feeling eyes upon him, Severus set down his fork and looked up. "Yes? Was there something else you wished to say, Harry?"

"Uh . . .no.  Except . . .thanks for saving me again, Dad."

"Thanks for saving us both," Katie added.

Severus coughed, embarrassed. "You are most welcome."

"Happy Halloween, Dad," Harry said, smiling back.

"Happy Halloween, Professor."

Severus felt his mouth twitch up into a small smile in spite of himself.  What had started out as a tragedy had ended happily after all. And for the first time in a long time, Severus Snape actually enjoyed Halloween. He finished his pie and bid Harry and Katie good night before locking up and returning to his apartments.  Tonight had been a Halloween to remember and tomorrow was another day, troublesome students, exploding cauldrons, and all.