Welcome to Gotham City's heart of darkness. Arkham Asylum is a festering depository of the vile, the dangerous and the delirious, with an ever-growing population courtesy of the Dark Knight. But when Batman foils the Riddler's latest caper and a crucial piece of evidence, a thumb drive, ends up hidden in Arkham, potential salvation comes from an unexpected source: a covert government strike team assembled from Gotham City's underworld. The assassin Deadshot leads the team, code-named the Suicide Squad: Harley Quinn, Killer Frost, Captain Boomerang, King Shark, and Black Spider, a roster of rogues who know Arkham Asylum and its residents all too well. Batman is pursuing the thumb drive as well. After defeating a Suicide Squad member, Batman switches costumes with him and covertly infiltrates the Squad.