There was a giant SPLOOSH as Dean Winchester dove into the ocean. His small Zodiac rocked on the waves caused by his entry, casting a dark shadow over the depths below. Dean used the chain of the anchor to pull himself down into the cool water towards the sunken wreck. All he had to aid him in the inhospitable world below the surface was a pair of flippers and two lungs full of air.

As a treasure seeker, Dean preferred to do things the old-fashioned way. He had learned to deep-sea free-dive from his father, who had been a Marine. He had always loved and respected the ocean from a young age and knew that his destiny was intertwined with its murky depths. His brother, Sam, had grown up the same way, but chose to leave his family at age 17 to go to college. He was now a noted marine biologist on retainer at Sea World in Queensland, Australia and two years ago Dean had moved to the Gold Coast to be near his little brother. Family was important to the Winchesters, especially since their father had died in a fishing accident when Dean was 22.

Dean's day-job was repairing boat engines and he did some custom painting for his Uncle Bobby's business, but his real passion was scouring the ocean for sunken ships and treasure. He had found this particular site last weekend but waited until he had a full few days off work to explore it properly. It was a small merchant schooner circa 1890 and, as far as he knew, undiscovered until now. As he swan down, his body shivered in anticipation. Who knew what sort of winders awaited him this time?

As soon as he reached the wreck, Dean took stock of what was readily in view. The ship was lying on its side, moored haphazardly on a sandy hill. The mast was in two pieces, cracked at the base with the largest part flung out over most of the main deck. The mast had been lost, but there was a spaghetti-maze of rigging still attached and Dean made a note to be careful swimming among it. Luckily, it looked like the hatch the lead below deck was open or broken, so the diver decided to start in the belly of the ship to see if any cargo was salvageable.

He ended up first in the crew quarters, which was basically a narrow hall in the middle of the ship with thin bunks on either side. Sailors rarely carried much in the way of personal valuables, so Dean swan past and into the top hold where the every-day items were kept. The cargo would be further below and he'd look into that all in good time. Dean spent a few minutes mentally inventorying what he saw, from the crates marked with food barrels of water and gunpowder to a few mysterious boxes tucked into a far corner. Thinking those looked promising, Dean dove a bit deeper to take a look.

Suddenly, Dean saw a flash of bright blue out of the corner of his vision. Curious as to its source, the man reversed his trajectory. He swam towards the open galley doorway in the hopes of finding what had caught his eye. Inside, the floor was littered with glass and china and the sun shone in through a hole in the hull, igniting them in a riot of murky color. He assumed that had been the source of the blue light, so he shrugged and swam closer to examine the remains of the ship's kitchen. There was not much of value, just a few unbroken plates and some silverware that might shine up nicely but weren't exactly treasure material.

After the galley, Dean dove deeper into the belly of the ship, looking for the captain's quarters near the back. Other than the hold, he knew that that room might have the most to offer in way of treasure. Eventually he located its location but met with a frustrating obstacle—it was completely blocked by a mass of wooden crates and deck rigging. Most of the crates were still full of whatever they had been made to carry and after a few half-hearted tries at moving them, Dean knew this wasn't going to be a one-man job. If he was lucky, he might be able to shift them enough with the help of his boat, but it would be slow going.

Dean was so busy calculating how much rope he was going to need and if he had enough on the Zodiac to get started today, that he missed the flicker of grey that glinted off an unbroken window. A flurry of movement finally caught his attention and Dean turned just in time to see a huge grey shape swimming towards him at top speed. Dean let out a yell that translated into a stream of bubbles and thrust himself back amid the deck debris.

The shape slid past him and Dean got a good enough look to identify it as a bull shark. It was at least six-and-a-half to seven feet long and bulky, probably a male. And it looked hungry, judging by its gaping maw. Dean had to make a decision fast—did he attempt to hide deeper in the ship where the shark couldn't get him and risk running out of air, or should be make a run for the Zodiac and hope he could out-swim a shark?

In the end, Dean decided to flee. His startled gasp a moment ago had robbed him of a lungful of air and he was already nearly at his limit.

As the shark made a wide U-turn in order to come back around to get the diver, Dean steeled himself and thrust away from his hiding spot behind a crate. He didn't look behind him to see if the shark followed his movement but concentrated on putting all his strength into swimming for the surface and the dark shadow of the Zodiac's bottom. The flippers on his feet turned out to be more of a hindrance than a help—they were made for diving, not speed—but he didn't have the time to remove them. Every second counted as he sped towards the fresh air waiting above.

He was almost clear of the ship when suddenly something yanked his right foot, forcing him to stop and jerk backwards. For a horrible moment, he thought the bull had gotten a hold of his leg, but a quick glance revealed his flipper was caught in a length of rotted rope that had been floating above the ship. He shook his foot desperately, hoping the rope would give and break but it stubbornly held fast.

The shark sped past him once again and then turned around laboriously, confused by his prey's sudden pause. Dean reached down to attempt to free himself from the rope or the flipper, but the shark was coming too fast, mere yards away. Dean winced, bracing himself for the bloody impact.

It never came. At the last moment, a streak of bright blue whizzed past him in the water and thudded into the shark's side, throwing it off course. The two figures spun away from Dean, giving the man more time to wrestle with the rope. He tried to keep his eyes on working the fin off his foot, but he couldn't help looking to see what had saved him.

At first he thought it was a dolphin. The playful, intelligent animals had been known to attack a shark if one of their pod was in danger, although Dean hadn't seen any dolphins around and he couldn't guess why one had randomly decided his ass needed saving. But, dolphins were generally grey and the thing that had swum past him was blue. A big fish perhaps? But, again, he'd seen nothing that big around the wreck and it would have no motivation to attack a bull shark on his behalf.

The shark pulled out of the spin first, swimming in a wide, stunned circle while trying to get its bearings. When Dean saw the other animal, he lost what little breath he'd had when he gasped in shock. What had saved him was not an animal at all. Or, at least, not 100%. Dean wouldn't have believed it if he hadn't seen it with his own eyes, but at the moment he was faced with undeniable proof that mermaids were real.

Well, to be more specific, merman. The creature that had saved him swirled around in the water, also a little dazed from hitting the shark head-on. When it straightened and began to swim in his direction, Dean could clearly see it had a man's slim torso that blended seamlessly into a long blue fish tail. He would have liked more time to acclimate to this astounding discovery, but he was currently out of air and at this point struggling mightily to free himself.

The merman came nearer and Dean briefly panicked. Just because the thing had saved him, didn't mean it was entirely friendly. He ignored Dean's floundering and went straight for the rope, beginning to help untwist it with a determined expression on his face. Since the merman was in a better position and seemed to be in the mood to keep helping him, Dean let go and pulled his head up to look for the shark. It was coming out of its circle and looking around for its missing prey and new attacker. It spotted Dean and gnashed its teeth, gunning back in his direction. Dean was too stunned by the sight of the great fish coming at his that he stopped moving and floated helplessly.

Something smashed painfully into his side. Dean felt a flash of pain as his foot was yanked free of the rope, probably twisting his ankle in the process. His lungs burned for air, but he turned to see what had happened. The merman was swirling away from him into deeper water, the source of the impact. A trail of dark green and red fluid followed it and it didn't take a genius to figure out that the merman had pushed Dean out of the way and gotten bit by the shark instead. The bull clearly smelled the blood, as it stopped on its way to Dean and turned, swimming for the merman instead.

Dean swam in the opposite direction. He turned away from the shark and the merman and rocketed towards the surface as fast as his tired legs and arms could propel him. Along the line of the anchor he went, following the metal chain up to where he'd left the Zodiac. He broke the surface with a mighty splash and a desperate breath of fresh air. He gulped down as much oxygen as he could while he held onto the side of the Zodiac with one hand. The other fished for something he kept near the edge of the little boat. When he felt the cool metal touch his hand, he grabbed it and with one last lungful of air, he turned and dove back into the water.

It was easy to follow the string of bubbles created by the fight between the bull and the merman. Dean watched as he swam, mentally cheering the merman as he used his tail to hit the shark's nose, drawing blood. The shark got a piece of his tail fin in its teeth though, ripping through it so it flapped uselessly as the merman tried to turn away. Dean gritted his teeth, coming back behind the shark. He had just one chance to make this work. Treading in the deep water as gently as possible, Dean took careful aim. Just at the shark turned towards his scent, Dean let loose the harpoon he'd brought, flinging it downward with all his might. It sailed true, embedding into the shark's gills. A cloud of blood blossomed forth from the fatal wound and in the shark's last thrash of anger, Dean briefly lost sight of his savior.

The man dove down, getting past the shark's blood, looking for the merman. He had been hurt pretty badly as well and Dean needed to know it was ok. It took a long minute, and then Dean finally spotted him lying limply over the bow railing of the ship. His tail swayed lifelessly in the churning water and for a terrible second, Dean was afraid he was dead. He came upon the merman and at last saw the wound that it had sustained while saving him. There was a half-moon of the bull's teeth marks along the merman's side, covering half his human hip and upper fish tail. The punctures were still seeping blood—green from the fish side and red from the human.

Dean tried to feel for a pulse under his neck. His human skin was chilly, but Dean wasn't sure if that was normal or not. However, his fingers slid across a pair of slits just behind the merman's jawbone—gills, Dean realized—and he saw that they were still taking in water. That was enough for him. He grabbed the creature under one of its arms and hauled it up, adjusting his grip so he wouldn't let go. He used the wooden ship rail as a springboard, launching them up towards the surface. They passed the falling shark on the way, but Dean didn't spare it a glance. He was too busy thinking about how the hell he was going to save a freaking merman.