Some secrets are a poison. His father's was a plague.

Dr. Alistair Finch, a brilliant pathologist haunted by the past, has spent fifteen years building a sterile, quiet life, a fortress of science against the grief that shattered his family. He is a man who deals in cold, hard facts. But a call from the decaying coastal town he once called home drags him back into a world of myth and madness he can no longer explain.

Port Blossom is dying. A mysterious, phosphorescent algae bloom is strangling its harbor, and a deeper sickness is infecting its people. A series of horrifying, ritualistic murders has begun, each victim left with the same impossible signature: the Siren's Knot. As the town's official coroner, Alistair's scientific mind rebels against the folklore and superstition taking hold, yet he cannot deny the evidence before him. The victims aren't just being murdered; they are being driven to their deaths by a terrifying, hallucinatory song that seems to rise from the bloom itself.

To uncover the truth, Alistair must dig into his own family's toxic legacy and the illegal genetic engineering experiments of his disgraced father. He soon discovers the murders are not random acts of a madman, but calculated messages in a campaign of vengeance, and every clue points back to the tragedy that took his sister. Now, with the local sheriff viewing him as a suspect and the town descending into a violent witch hunt, Alistair is completely alone. He is the only one who understands that the true killer isn't just a person; it's a sentient biological weapon that is turning the town's own residents into monsters.

Trapped between a brilliant, manipulative killer and a town losing its mind, Alistair must confront the devastating truth of his inherited guilt. He must face the monster in the water, the monster in the community, and the monster in his own bloodline if he is to have any hope of stopping the final, terrible "baptism" the killer has planned for the coming dawn.