When a power struggle breaks out and a group of criminals tries to take over the city, Harley Quinn finds herself up against new obstacles as Gotham City splits from the United States.
Harley and Ivy infiltrate the city's university disguised as two university students. Their goal is to arrest the Riddler, who has become the university's dean and is planning evil actions targeting the students.
In an epic struggle to face Mr. Freeze, Harley Quinn teams up with Ivy on an impossible task and recruits Catwoman to assist in stealing a flamethrower.
Harley begins to pursue Freeze on a revenge mission, while Ivy and Kite Man delve into the details of their wedding, and threads of love, revenge, and crime are intertwined during the events.
After Harley killed his friends, Bruce must face the sad truth that he cannot protect Gotham because of his injuries. Bane also demands that Two-Face join him in his crimes, while Batgirl makes an appearance to combat Gotham's enemies.
The Joker appears in a completely different form before the eyes of Harley and Ivy, and they wonder if a person can change. They remember Harley's first day in Arkham Hospital, where criminals with mental illnesses are imprisoned.
Two-Face decides to send Harley Quinn and Ivy to Bane's deep underground hole, while Jim Gordon and Batgirl set out to reclaim Gotham Police Headquarters from Two-Face's control.
Harley escapes from the awkward kiss to the furthest possible location on the planet Apokolips, and from there, she seeks to obtain an army and invade Gotham City in order to take revenge and regain her status.
Harley brings Ivy and the other girls to Themyscira for a bachelorette celebration. Events proceed as King Shark arises.
On Christmas Eve, Harley, who suffers from loneliness, contacts the Joker, and they go together to Bruce Wayne's Tower before the escaped Riddler and the army of Para Demons unexpectedly interrupt their romantic dinner.
Harley seeks to defeat Psycho's army with the help of the Joker, so they embark on a dangerous journey to find the storybook that Fables owns and capture the good heroes inside it.
Gotham City collapses under the weight of the power of Psycho, who controlled the minds of Ivy, Clayface, and King Shark, then he put them in a heated confrontation in front of the good heroes.
Harley ruins Ivy's wedding in order to prevent Officer Gordon and his men from interfering, and events take an unexpected turn. Will Harley succeed in carrying out what she intends to do?