Dazai Osamu is a brilliant, reserved marine biologist known for his unwavering belief in science and skepticism toward anything unprovable. He’s spent years studying the sea’s depths, cataloging its creatures with precision. But everything changes when he's summoned to a remote island after locals report sightings of an unknown creature — something part human, part fish.

Expecting a misidentified marine animal or perhaps a case of island folklore, Dazai investigates the claim with scientific curiosity. What he finds instead is something no textbook could prepare him for, a living mermaid — injured, intelligent, and undeniably real.

He should have reported it, he didn't.

Day 1 — dazai's diaries I found it. That’s the only way I can begin this entry, because anything more sounds like madness.

The ~~fish~~ 'mermaid' was tangled in a fishing net, barely conscious, it's skin glimmering like a pearl. Eyes too human to ignore. Definitely had a tail, not a costume, not an illusion, Real, Muscular and iridescent, evolved for deep-sea movement.

I brought the specimen back to an abandoned research facility, I don’t know with certainty what it is, I mean, could this actually be a living, breathing mermaid?

Dazai was sitting by the edge of the pool where he had the mermaid contained, it was a hassle to bring the creature here, he was looking at it and the creature looked back at him.

"Hi there..." He whispered, wondering if the creature had the ability to communicate, even if it was in its own language.