This would is set sometime during S14 after Jack loses his powers.

24. Drowning

The scream ripped across the water and Castiel sped up on the heels of the Winchesters.

"Look!" Jack cried, pointing out into the lake.

A young girl was trying to swim to shore as fast as she could but there was something behind her. There had been several drownings in the area, and they had found out the culprit was a kelpie, a carnivorous water horse that would drag unsuspecting passers-by into the water where it would drown them and proceed to have them for supper. It looked like it had just found its next victim.

They raced out onto the dock and Sam bent to untie the boat that was there, but Castiel knew they wouldn't get to the girl in time.

Jack seemed to see that too, because he suddenly raced back to the shore.

"That will take too long! It's going to kill that girl!"

"Jack!" Castiel shouted, reaching out to stop him, but Jack was already running into the water and hurrying as fast as he could over to the girl who was flagging.

"Can he even swim?" Dean asked, as they finally got the boat untied and he and Sam got in it, guns at the ready, with wrought iron bullets. The kelpie was a fairy creature and so iron was their best bet at making sure it stayed dead.

"No," Castiel said. "You go out on the lake, I'll help him with the girl."

Castiel ran back to the shore and stood, watching with bated breath as Jack got to the child as quickly as he could. But the kelpie was right behind them.

"Jack, be careful!" he shouted.

Dean raised his gun as Sam rowed, and shot near the place where the kelpie was disturbing the water.

Jack finally got to the girl now that he was chest deep in the water and reached out to grab her. She clung to him frantically. Castiel threw his coat off and was already wading into the lake to help when Jack suddenly cried out and was jerked backwards.

"Castiel, take her!" he cried, shoving the screaming child away from him before he was dragged under.

"Jack!" Castiel cried, echoing Sam and Dean's shouts from twenty yards away. He fished the crying girl from the water and hurried back to the shore, wrapping her in his coat to keep her warm in the chill air.

"Stay here," he commanded and then ran back into the lake, swimming out to the place where Jack had disappeared.

"Do you see him?" Castiel called to the Winchesters.

"No!" Sam shouted back as they rowed closer.

Castiel dove down into the lake. The struggling had stirred up the sandy bottom and it was almost impossible to see, but Castiel finally caught some movement and frantically made his way toward it.

He reeled back as the kelpie suddenly appeared in front of him, its oddly sharp teeth horrifying in the mouth of the small pony-like creature.

He lashed out with his blade, catching the creature across the shoulder and it streaked away. He let it go. The Winchesters would deal with it; he had to find Jack.

As he swam further, he found a path of weeds that were thick and tangled. He searched frantically, clawing through them, when he found a bloated piece of arm. He reeled back in horrified disgust. This must be the kelpie's nest, where it kept its victims.

And then he saw a dark blue jacket, the same Jack had been wearing, and he swam forward, digging through the weeds until he unearthed the boy. Jack was limp, his eyes closed. His right ankle was bleeding, probably from where the kelpie had clamped its teeth in him to drag him down.

Castiel gripped him by the back of his coat and started swimming toward the surface.

When he finally broke the surface, it was to the sound of gunfire and a horrible braying shriek.

"Cas!" Sam's voice came from nearby, and Castiel turned and saw the boat coming toward him. Dean leaned over the side, his gun pointed at the water where Castiel saw a red stain spreading.

Sam reached a hand over the side and helped Castiel haul Jack's limp body into the boat then he climbed in himself.

"It's dead?" Castiel asked Dean.

The hunter nodded. "Yeah. How's Jack?"

"Not breathing," Sam said, crouching beside the boy. Castiel felt a pang in his chest and watched as Sam laid Jack flat and cleared his airway before he started to perform CPR.

Castiel and Dean watched with bated breath as Sam continued, trying to get the water out of Jack's lungs, and then finally, the boy's chest spasmed and he jolted back to consciousness, water gushing from him. Sam and Castiel both reached to steady him, and help him onto his side so he wouldn't choke as he brought all the water up.

"You're okay, you're okay," Sam murmured, relief on his face as he patted Jack's back.

Jack let out a gasping sob and sank back against them before he looked around frantically, trying to get out of Castiel's hold, even though he hardly had any strength.

"The girl…" he gasped. "And the kelpie!"

"The girl's fine, she's on the shore. You saved her," Castiel reassured him.

"And the kelpie's dead," Dean added.

Jack shuddered, wrapping his arms around himself. "I…I thought I was going to die down there."

"Jack, you know we'll always come for you," Castiel told him softly, reaching up to brush the wet hair out of his eyes.

Sam shrugged out of his jacket to wrap around Jack's shivering frame. "You're gonna be put into those kinds of positions while hunting—believe me, we've all had our fair share of harrowing spots." He glanced between Castiel and Dean. "But we always have each other's backs."

"We always get each other back safe," Dean added firmly and reached for the oars. "Now let's get back to shore so you can dry off and we can get that kid back home."

Jack nodded and huddled in the bottom of the boat between Castiel and Sam, obviously still shaken, but all right. Once they patched up his ankle and got him some dry clothes, he would be fine. Castiel was grateful.

"I think maybe I should learn how to swim," Jack said after a while, and Sam chuckled, nodding.

"That would probably be a good idea too," he said.