Harley Quinn is fed up being the Joker’s sidekick and strikes out on her own – determined to become the criminal Queenpin of Gotham City.
Determined to become one of the vaunted Legion of Doom, Harley attempts to make a big splash by crashing one of their criminal enterprises with the help of her BFF, Poison Ivy.
Realizing she needs a crew to pull off heists that will attract the Legion of Doom’s attention, Harley attempts to recruit Dr. Psycho and Clayface.
In search of a nemesis, Harley goes after Batman, but ends up with an adolescent Robin, making her the laughing stock of the criminal underworld.
When Harley suffers a paralyzing identity crisis, her crew must enter Harley’s mind to free her with the help of Dr. Psycho’s telepathic powers.
When Clayface loses his arm in a heist, it turns out to be not only evidence for Jim Gordon, but also a key witness against Harley and her crew.
Harley recruits her friend and mentor Queen of Fables to help her steal a force field from STAR Labs, to steal a weather-changing machine, so she can impress the Legion of Doom. Meanwhile, Poison Ivy dates Kite Man.
Harley gets an invite to the Legion of Doom’s prospective members party, but Ivy discovers that it’s Lex Luthor they’re really after.
Now a member of the Legion of Doom and The Joker’s equal, Harley finds herself spending time with him. Will she slip into her old ways?
After a falling out with her crew, Harley heads back home to Bensonhurst, where her doting mother waits for her... and her deadbeat dad, who’s more dangerous than anticipated.
Harley must rescue Ivy from the clutches of Scarecrow, who’s trying to harvest her pheromones to make a super toxin that turns plants into sentient monsters.
Harley thinks the Legion of Doom is behind Ivy's capture and the tree monsters currently ravaging Gotham. But it's a trap!