Da Gothams mest berygtede og narcissistiske skurk, Roman Sionis, og hans højre hånd, Zsasz, udlover en dusør på den unge lommetyv Cass, træder Harley Quinn og co. til for at redde hende.

When his wife and daughter are senselessly murdered, a grieving man finds himself caught up in a war between a group of charismatic vigilantes and the crime that infests their city.

On Halloween night, a serial killer returns from the dead to take revenge on the vigilantes who put him to death one year earlier.

The Three Mesquiteers are forced to track down a train robbery ring after some of the gang hijack their truck for a getaway and the police conclude they are part of the gang, an identification which is just fine with the gang's nameless chief.