I somehow ended up watching a video with scenes from the movie Splash! which I loved when I was a kid. I was thinking it would make a lovely fusion fic, but which of my ships? It kind of seemed obvious it should be Draco and Neville, with Draco being the merman.
Perhaps one day at Hogwarts, first year Neville finds himself drowning in the lake, being pulled down by a grindylow. A merboy saves him, but is called away by his father, and Neville is pulled out of the water by Professor Sprout. No one believes him that it was a merboy that rescued him, because the merfolk have a bad reputation. Dumbledore believes him.
He always thinks of his encounter with the merboy. Years later, he is Sprout’s apprentice, and on the last day of school for the year, he accidentally falls into the lake again. He wakes up on the shore, and there is a mysterious man standing over him with eyes the same color as the lake during a storm. Neville whispers, “Who are you?” The merman looks down at the Hogwarts crest on Neville’s jumper and croaks, “Draco...” Neville thinks he means that’s his name. Draco kisses him, then runs away. Neville passes out again before seeing that Draco’s going back into the water.
Neville goes off to London for the summer to spend time with his friends and work at a greenhouse that supplies the local apothecaries. Draco finds out he’s gone to London, and swims down to the Thames and climbs out, seen by a muggle before he transforms his tail to legs. The muggle becomes obsessed with finding him again. Meanwhile Draco finds Neville and they fall in love, with Draco hiding his true form from Neville.
Eventually the muggle finds Draco, and reveals his true form in front of a crowd of London muggles. He’s captured and examined by muggle scientists. For some reason the MoM wash their hands of him, Neville’s friend Harry thinks it’s because someone in the Ministry hates merfolk, considering them dangerous (shades of how they were with Buckbeak). So Neville and his friends stage a breakout.
They rescue Draco, but they are chased and eventually cornered. Draco dives into the Thames to make his escape. Neville can’t bear to let him go, so he dives in after him. Draco reveals that Neville can breath underwater as long as they are together. Neville is fine with living the rest of his life that way, since there’s just as many plants in the sea as on land. They eventually end up back at the lake at Hogwarts.
