A botched police operation results in the suspension of those involved: Officer Wilkes, Officer Montoya, and Detective Bullock. Confronted by their superiors, each of them is forced to tell their tale of what happened that night.

Joker creates a toxin that affects only fish, mutating them into Joker fish. Then, he targets innocent men who refuse to copyright his Joker fish. The Joker also captures Harvey Bullock, and Batman must rescue him and foil the Clown Prince of Crime's insane scheme.