Six months after the black out caused by the League of Assassins, new District Attorney Harvey Dent is trying to put a stop to the mask and cape crisis. Batman finds himself being framed for an attempted attack on the life of Mayor Grange and takes drastic action to find out who is responsible.

Batman, Katana, Commissioner Gordon, Mayor Grange, and Tobias Whale all wake up after being drugged and kidnapped by Humpty Dumpty. According to Dumpler, there is a culprit among them and the only way to escape his Murder Mystery Game is to figure out who. With each clue, however, the game becomes deadlier and begins to take its toll on Batman who's obsessed with solving the mystery and defeating Dumpty. While trying to figure out one for the clues, Katana questions Batman priorities. It soon becomes clear that all of them had a part to play in the ruining the life of an innocent man, name Ernie: Whale for smuggling and letting him take the fall, Batman for giving the tip on the shipment, Gordon for the arrest, Grange for sentencing him to prison meant, and Katana for getting the weapons, including Dumpty, who stood by and did nothing. Dumpty has brought the man who all of them are responsible for ruining his life, and give him the chance at revenge, but he refuses. Dumpy tries to destroy them, but Batman states that he is as guilty as they are. In the end, Ernie is set free, while Humpty and Whale are arrested. Gordon lets Batman and Katana go. Batman lets Katana go for awhile for questioning him.