For some unknown reason The Joker has been released from Arkham Asylum. After being tailed for a little while by some some hired thugs that are possibly cops, sent to kill Joker, Jonny drives Joker to Killer Croc's hideout, a few of his former goons at a bar in a strip club are talking about who should go pick him up, and Jonny Frost volunteers to go get him fromsically a big meat freezer, Croc asks how the Joker got released from Arkham but Joker refuses to tell. Croc asks if Joker would like to join them in their game of cards, but the Joker is broke and recruits Croc and his gang to help him recover what was rightfully his and more.
The story is told from the point of view of Jonny Frost who wants to be somebody in the criminal underworld, and he believes that tagging along with the joker will help him rise up in the ranks. Joker, Croc, and Frost go to the strip club from the beginning and celebrate Joker's release with Monty, a former goon who was sent Johnny to go get the Joker from Arkham. Harley Quinn is among the strippers at the club and puts on a little show for the patrons. Joker, Harley and Monty go into a back room to "discuss" what has happened since the joker has been gone, and some time later Monty stumbles out, skinned alive, and collapses on the floor. The joker takes to the stage and talks about how the people he he thought were capable of running the city while he was gone basically "took a dump on it" and asks who wants to help him take it back. In his head, Johnny says he does. Two-Face receives a call about the Joker's release and what has transpired since he's come back.
The next day, hungover from the party Johnny drives Joker and Harley around town, Joker asks Johnny to stop at a bank as he needs some money, while in the bank Jonny reminisces about where he's been in his life thus far, shortly out of prison after his fifth term, and has recently been divorced from his wife Shelly. Joker returns with a bag full of money, he said he didn't kill anyone in the bank this time, and asks Jonny to dispose of a bloody picture of the Bank President's daughter. Joker later arranges a meeting with Penguin as he needs the money increased ten fold, and demonstrates that Croc is acting as the Joker's muscle. Jonny returns to his apartment to collect some things, and finds that a cop is waiting for him in his apartment, and tell's Jonny he's running with the wrong crowd. Later that night Jonny drives the Joker to meet with Tommy Bang-Bang, a former underboss of the Joker's, and the Joker states that he knows that he is out there watching him, and waiting. Joker wants what is his back, and after getting a cut from Tommy, says he still wants Tommy and his crew to run his operations for him, he walks out of the restaurant, then returns and shoots just Tommy, telling the crew that the offer is still on the table for them but at a lower pay rate. He walks outside and as if Batman was there says "Not good enough for you? Need me for more of your dirty work? I admit I aimed low" and does a russian roulette on himself, survives than bursts out laughing. Over the next few weeks bodies start piling up and jonny relishes the fact that few knows where they all are buried. Joker goes to visit Penguin to collect his money. Penguin comments on how Two-Face has become very angry with the Joker because of his actions as of late. Joker and his crew return to the strip club from earlier and after unsuccessfully trying to reach Two-Face, flips out and kills one of Croc's goons, declares war on Two-Face and proceeds to burn down the club.
The Cop from earlier finds Jonny at a Diner, and brings him before Two-Face, who wants to put him on his payrolll as the cop is, and warns him that he is dealing with a man that will stand over him as he is dying and will laugh. Shaken by the meeting, Jonny stands for hours on top of a skyscraper and thinks, causing him to be late to the meeting the Joker has scheduled with the Riddler, who presents the Joker with a suitcase, when the suitcase is opened, it emits a gold glow a la Pulp Fiction, and tells Nigma to get out of town. While driving away the group is attacked by Two-Face's goons, and while trying to escape on foot the Joker encounters The Cop, who is shot in the head by Jonny before he can pull the trigger on the Joker. Two-Face finds his body hanging upside down from a tree outside his mansion with a smile cut into his face. Over the next few days the Joker's men hit hard on Two-Faces businesses, until a meeting is scheduled at the Gotham Zoo between the two. At the Zoo Two-Face reveals he has Jonny's wife revealing that he has met Jonny before, Joker tells Two-Face he knows about some wives he has had with women , stating that "you can get away with murder, but not with wives" and could get Harvey charged with bigamy, while saying this he pulls off one glove. Two-Face reaches for his phone saying he could call someone to make it all dissapear, but the Joker reaches for his phone, he doesnt get the phone, but he slashes Harvey's wrist several times because of the glass shards that he has stuck into his fingers. Two-Face's goons are then killed by Harley who was wearing a Gorilla Suit, and Joker tells Two-Face he doesnt care about money, and whispers something into Harvey's ear that makes him go wide eyed. Joker has sex with Shelly, Jonny's wife, and then calls them even for Jonny saving his life.
Joker then proceeds to go on a rampage seeing the city as his "sandbox" with such acts including the robbing of a liquor store, and killing an elderly couple with a straight razor simply because he can. Jonny starts to realize the horrors he has gotten himself into. An impromptu Bat-Signal made by Two-Face alerts Batman and he tells him that the Joker has found away to destroy one "us" referring to his two minds. Batman then proceeds to take out the Penthouse where Harley is staying and Croc's hideout, causing the Joker to go into a panic as he knows Batman is finally coming for him. Fleeing on foot, and seeing the Joker under pressure Jonny starts laughing manically, and is pistol whipped and taken as a human shield for protection against Batman, being confronted on a bridge the Joker demands to know why Batman lets his mouth and jawline be seen despite wearing a mask, Batman's repsonse is "to mock You" which causes Joker to shoot Jonny in the neck, fatally wounding him. As Jonny bleeds to death and watches Batman fight the Joker his inner monologue states as a man on the top looking down he now sees the Joker as a disease there is no cure for, just a Batman.