Whumptober but it's in a different month and it's the 12 days of Christmas 

"I hear something," Superboy stated. In the space of seconds, the cave they'd been told had been free of flash floods for the last year, experienced a flash flood. A wall of water came barrelling around the corner and they had just enough time to recognise they were about to get hit hard before they were swept off their feet.

Aqualad was quick to gain his bearings and grabbed whoever was closest to him, those being Artemis and hanging onto Artemis's boot was Kid Flash, before swimming to breach the water line in hopes of finding an air pocket. Miss Martian added some gills to her form and grabbed onto Superboy with the same mission. They had no idea how fast or how far they'd been swept away, especially in the pitch black of the cave but they knew it wasn't good. A current tried to push them in every which way, desperate to add more bodies to its kill count but by some miracle they'd discovered between the water and the ceiling of the cave, they had a good few feet.

Putting his bio-illuminance to good use, Aqualad lit up the cave and directed Miss Martain to a small platform to give them a place to wait this out. They fought the water until they could safely drag themselves and their drenched teammates.

"So much for no flash floods," Wally snarked as he coughed. He wasn't sure if he'd swallowed water or just been hit by the wave so hard it had knocked all the air out of him. He swore water had hit his nose so hard there was some in his brain. His teammates let out exasperated breaths that he assumed to be tired laughs. 

As he glanced around them, their faces washed in blue light, he noticed they were missing someone. "Robin?" he called out in case the younger was pulling another stupid ninja move.

Water still flowed in but they were behind the initial gush of it, preventing silence but insisting on quiet. Lumps appeared along the water line but they could easily tell it was debris. Wally felt his heart leap to his throat as he realised that he hadn't received an answer not to extend an ill-timed practical joke but because the person he was asking for couldn't reply. He wasn't here.

"Robin!" he shouted, his voice bouncing off the walls and echoing back to him.

"He's around here somewhere," Artemis insisted because the thought of him not being there was impossible. There was just no way he couldn't be with them.

"I can't see him," Wally whispered. "Where was he?"

"Behind me, I think," M'gann answered. "He was playing on his computer."

"He could've been knocked back further into the system," Kaldur suggested.

The sudden sound of water sloshing, the surface of it breaking, brought hope that they'd see Robin fighting off the current after somehow avoiding the worst. They gazed out across the cave but found no such thing. The water returned to calm whilst they returned to anything but. It was probably a stalactite falling. 

"Shine a light over there," Connor demanded, pointing in the dark. The light Kaldur provided could only do so much but he still tried to focus it on whatever his teammate was seeing. When he did, it still looked like nothing they didn't already see, until it shifted just right to catch the light.

"It's one of his lines," Wally concluded. "He's still in the water."

"Is he pulling himself out?"

"He'd be out by now." Kaldur didn't waste much time thinking his decision through before he swam to the line. He could feel the water desperately trying to pull him under and shove him back through the cave system. He was glad to have spent so long battling the sea currents for fun on the days he wasn't training. He took the line in one hand and dove beneath the surface, keeping it in a tight grip as he followed it down.

Batman didn't offer much survival training when it came to water. Gotham had a few rivers but they thankfully lacked in water-themed villains. Still, he was a paranoid man. Robin had learned to swim long before the fateful fall of his parents but received some endurance training if he ever got caught in unexpected rapids. He learned to hold his breath for long periods of time and practised getting a breathing apparatus on until he could do it in seconds even when he was caught off guard. 

When the water hit him, Robin did as he was trained. He quickly grabbed his rebreather and shoved it in his mouth so harshly he nearly knocked out a tooth. He curled into a ball as he was caught in the wave and shielded his head from impact. The water was foggy from picked-up debris and mud but he felt himself hit something hard enough to keep him in one place. He didn't know which way was up or down but he knew he had stopped as the water forced its way around him to continue its path of destruction. He couldn't be sure how far he'd been flushed out and he could only hope that his teammates were fairing better than him.

It took a minute to reassure himself that he was indeed still alive and that his rebreather would give him some sort of safety before he planned on getting himself out. If drowning didn't kill him, staying in the freezing water would. He reached for his grappling gun, knowing it would have the force to break through the surface but he didn't know where that was. It was too dark to see. Initially, he wondered if he'd ever opened his eyes but he could feel them sting so he knew they must be.

He knew he had to take the rebreather out. Even in the darkness, he would be able to at least feel which way the bubbles would go. He put one hand over the rebreather and stretched his arm out a few inches away to feel the direction of the bubbles. Then, as though ripping off a bandaid, he snatched the rebreather out of his mouth and forced himself to exhale. The bubbles rushed past his fingertips and he quickly reinserted the rebreather before the water raced to fill his mouth. He took his grappling hook and followed his arm, cupping the trigger before pulling. He prayed that it got a good grip on something. 

When he felt the line go taught, he debated retracting the line. If it was hooked onto something, it could pull him out of the water. Unless it hadn't ever left the water and he was far away from anything even resembling an air pocket. If it wasn't hooked and he tried to bring it in, he'd be back at square one. The team might've been able to see it and he would've lost his chance at being found. That was if they were even alive to think where he was.

His trigger finger itched. He was freezing. He could practically feel ice building up in his joints, locking them in place. Thermals could only do so much. His rebreather could last up to six hours but hypothermia would get him first. He clung to the gun. If his body were going to freeze, he'd rather it freeze clinging to the only thing that could lead an investigation team to him dead or not. Robin closed his eyes. 

Kaldur and M'gann could survive. Kaldur was Atlantian and whilst he was used to clearer and warmer waters, he'd be more adept to the environment. He'd likely grab whoever was closest and bring them to the closest air pocket. M'gann could change her biology and become amphibious. She could collect all of them together after they were strewn apart by the initial impact and bring them to the surface. Both would likely save the others which meant they were more than likely to start asking where he was.

It would be hard for either of them to see in the murky water so the grappling line would be best left where it was. He'd have to play the waiting game but he could be assured that they would eventually look for him. He took his finger off the trigger and instead wrapped the line around his wrist in case he lost his grip or another gush of water tried to take him out for good. 

The line seemed to go on forever. There was nothing to give him a sense of time nor progression but Kaldur had decided the moment he saw it that he wouldn't stop until he found something. Even if it was just an abandoned grappling gun that had sunk to the cave floor. The deeper he went, the colder he got. The water had already been freezing when he entered and although he wasn't sure on how long humans could survive in these temperatures, he knew it wasn't long enough for this to be a dead end.

Eventually, something came into view. Whilst everything in the water was dark and hard to distinguish, what he saw was malformed. The line continued. He got closer. Relief rushed through him when his hand found the end of the line and the gun it was attached to. The light emanating from his body shone bright enough for him to see the fingers on the trigger and highlighted enough limbs for him to understand that what he saw was indeed his teammate. He didn't have time to investigate if Robin was alive or if he'd succumbed to drowning. All he could think was to grab him now and get to the surface. He didn't care if this was a rescue or a recovery. He just knew he had to get Robin to the others.

Kaldur grabbed his hands and followed them to his shoulders, grabbing him around the torso. He pulled the younger close to him and followed the line back up so he wouldn't get turned around in the water and lose valuable time. He did his best to ignore how Robin was deadweight against him. He had hope that since Robin had a rebreather in and how he'd been able to shoot his grappling hook to alert people to his presence, they would be able to tell this as a morbid funny story after enough time had passed.

Between breaking the surface of the water and swimming back to the small sanctuary they'd found went by in seconds. It would've sent Kaldur reeling to have each second feel like an eternity to a minute going by in the blink of an eye but he was far too focused on the teen he'd brought to shore. Robin waited until he was firmly lying on something solid before seemingly coming back to life and sitting up by himself. He was shaking harshly, his teeth chattering around the rebreather and making an awful clicking sound against the material before he took it out to spare their ears. 

Wally had immediately jumped into wrapping up the younger in a hug and holding him close. Robin easily returned it if only to steal what little body heat there was to offer.

"I thought I lost you," the ginger muttered although there wasn't much use in doing so. The cave was deathly silent and his voice carried far further than he'd intended. He would've sounded less scared had he known that would happen. He would've waited for the shock to wear off and hidden his fear behind a joke. 

"Can't get rid of me even if you tried," Robin replied. "B is gonna get a piece of my mind though. No flash floods my ass."