The issue opens with the Joker reading about the Holiday killings in the newspaper. As the shot pulls back it reveals that he has bound and gagged a family in their home and is stealing their Christmas tree and the presents under it, all the while quoting various Christmas rhymes.
On Christmas eve Batman and Jim Gordon are in Arkham Asylum discussing recent developments. They are there to talk to the Calendar Man Julian Day to see if he can be of help in the Holiday investigation. While Day is more than willing to talk at length it is apparent that he knows nothing of any real value. Gordon and Batman quickly give up and leave.
Salvadore "The Boss" Maroni is at his restaurant with his goons speculating that Holiday may in fact be Harvey Dent. One of the members of Maroni's gang dies laughing and The Joker appears. He holds a gun to Marnoni's head and accuses him of being Holiday, because all of the victims have been from The Roman's branch of the Gotham mob. Maroni explains that the Holiday killings have ruined business for everyone, he tells Joker he believes Dent to be the killer. Later, after Joker has left and Maroni's men are attempting to dispose of the body he left behind Batman arrives. He shakes down Maroni and departs when he learns that The Joker was responsible for the murder.
Harvey Dent brings his wife Gilda out of the hospital and surprises her with the revelation that he has purchased them a new house. Gilda heads upstairs and as soon as she does Harvey notices that The Joker is in his living room. Joker strikes Harvey, leaving him in a heap on the floor. He threatens Harvey about the possibility of being Holiday. Joker states that he wants to be the only homicidal maniac in Gotham.
Joker appears in Carmine Falcone's bedroom, waking the gangster. He tells The Roman that the mob needs to kill Holiday, or The Joker will kill all of Gotham. As Joker is leaving the building he has a run-in on the porch with Falcone's personal bodyguard. In order to escape Joker pelts the man with his signature Joker cards and drives away.
As the bodyguard is still picking himself up he is shot. Left at the scene are an untraceable pistol and a snow globe. Holiday stikes again. Batman arrives on the scene and sees the Holiday victim surrounded by Joker cards and speculates that The Joker is Holiday.