A lone-wolf detective known as "The Shark" must navigate hostile territory within both the criminal underworld and his own corrupt department to hunt down a ruthless serial cop-killer in the streets of Shinjuku. Adaptation of the Arimasa Ohsawa novel Shinjuku Shark.

Miyako is a frustrated insurance saleswoman stuck in a major dry spell. She tries every trick in the book, including aggressive flirting, which gets her plenty of gropers but no buyers. One day while venturing down a narrow stairwell, she injures her ankle and happens upon Mitsuru who works for some mysterious foreign company. Decked out in high goth style -- complete with long inky black hair and mascaraed eyes -- Mitsuru cuts quite an odd figure, yet his seductive though menacing ways make him difficult for Miyako to resist. Escorting her to his office to treat her ankle, Miyako notices that his all-female staff seem more glassy-eyed and soul-deadened than the average office workers. In fact, they seem almost like zombies. Later, weird things start happening. Mitsuko finds vomit on her doorstep, she seems to be tailed by a shadowy woman in a red dress, and most strikingly, she finds herself utterly powerless against Mitsuru's advances. Soon she is offered a job at Mitsuru's office among the undead and the damned. Does Miyako's potential new place of employment at least offer stock options in exchange for her soul?