Following Scarecrow's poisoning of Gotham's water supply with Ivy's pheromones, trees are running amok all over Gotham Central Park, with Scarecrow and the Joker attempting to drive more people towards the park from other parts of the city. Batman peels off to obstruct them, dispatching Jim Gordon evacuate the park. Meanwhile, as Harley and her crew struggle to fight off the trees, the rest of the Justice League arrives and confronts them, believing them to be behind the chaos. As they are about to be sent to the Phantom Zone, Ivy convinces Wonder Woman to use her Lasso of Truth on her to confirm they are not, in fact, behind everything. After relenting and asking who is, Queen of Fables' book appears at their feet and sucks the league inside. Although initially grateful for helping them, Queen chides them for not killing her earlier and shoots them up to a castle in the sky via a giant beanstalk.
Unable to get down, as none of them can fly and Ivy is unable to control plants from fairy tales, the crew is soon confronted by a giant cyclops. Ivy is able to call Kite Man for help, but is questioned by Harley as to why she has his phone number memorized. While holding off the giant, Ivy admits she and Kite Man are dating, horrifying Harley (though not the rest of the crew, as they were all aware). When the giant grabs them and attempts to eat them, he is blinded by a packet of hot sauce from Kite Man, who helps them return safely to the ground where chaos has spread throughout the city.
As Commissioner Gordon drives a tank towards the park (despite being told not to by Batman), Harley commandeers the tank and attempts to use it to destroy the Legion of Doom's headquarters. However, the building is destroyed before they have a chance to strike, and in its place rises Joker's tower — using many of the suggestions given to him by Harley — announcing his rule over Gotham and contempt for the old Legion of Doom for letting Harley Quinn in. While Harley and company are thrown into disarray by the plant monsters, the Joker realizes that they escaped the giant and so he sends Queen of Fables to kill them once and for all.
Harley's crew attempt to figure out a way to draw away the plant monsters to access the Joker's tower, at which point Ivy notices that some of her pheromones are still in the water and that drinking some might transform her as she is part plant. However, before Ivy drinks, Kite Man "proposes" to Ivy even though he doesn't have any ring, so she pushes it off to deal with the apocalypse. After drinking, Ivy becomes a giantess and proceeds to regretfully attacks the plant monsters, drawing them away from Joker's tower to let Harley and the rest of her crew enter.
Before they get inside, the crew is confronted by Queen of Fables and Grandmother Wolf. The wolf is not fooled by Clayface turning into "grandfather wolf", and is only briefly stymied by Doctor Psycho telekinetically hitting it with a bench. Eventually the wolf pins Harley down and seemingly kills her, but King Shark quickly dispatches it, later saying "a lot of people ask me who would win between a wolf and a shark. It's a shark." With the wolf having had its innards eaten by King Shark, Harley wears its skin like a suit so that she can sneak up on Queen of Fables, at which point she knocks Queen of Fables' head clean off her body with a bat.
As the crew takes a moment to breathe and reflect on Ivy's new size, Harley is attacked by one last tree, which Ivy quickly takes care of and rescues Harley as she falls to the ground. Realizing Ivy was willing to attack the plants she loved so much to save her, Harley apologizes to Ivy for abandoning her, explaining she isn't used to people in her life treating her so well. Ivy sympathizes, agreeing that "most people are trash", and the two finally appear to make amends with one another after Ivy jokes about how messed up eating Harley right then and there would be.
Unfortunately, the reconciliation is short-lived, as Ivy is immediately pierced in the chest with a flagpole launched by Joker's tower. As she collapses to the ground and shrinks back to her normal size, Harley tearfully begs her to hold on, but to no avail, and Ivy apparently dies in her friend's arms. As Harley and the rest of the crew mourn their fallen friend, Joker keeps laughing maniacally from his tower, causing Harley to scream out in sorrow and anger.
Cast and Characters
- Kaley Cuoco as Harley Quinn
- Jason Alexander as Sy Borgman
- Diedrich Bader as Batman
- Lake Bell as Poison Ivy
- Ron Funches as King Shark
- Tony Hale as Dr. Psycho
- Chris Meloni as Commissioner Gordon
- Alan Tudyk as The Joker, Clayface
- Vanessa Marshall as Wonder Woman, Reporter
- Matt Oberg as Kite Man
- Wanda Sykes as Queen of Fables
- James Wolk as Superman
- "Devil's Snare" is likely a reference to the magical plant featured in Harry Potter and the Philosopher's Stone.
- The Justice League blame Ivy (and Harley's Crew by association with her) for the tree monsters. Despite there being clear evidence that they are running for their lives and not commanding the trees. This further shows the League makes bad calls.
- The Queen of Fables comments that Superman is sexy which is likely a nod to the comics where she was a stalker with a crush on him.
- This isn't the first time a harmless villain managed to incapacitate someone using hot sauce in Batman media as it happened in the Batman: The Animated Series episode "Make 'Em Laugh".
- This isn't Harley Quinn's first experience with tanks either which first happened in the BTAS episode "Harley's Holiday".
- During Ivy's battle against the tree monsters as a giant, she does a pose that pays homage to the poster of the 1958 film, Attack of the 50 Foot Woman.