Batman and
Nightwing discover that
Poison Ivy and
Floronic Man have teamed up and stolen information from
S.T.A.R. Labs about "Bio-Restorative Project" and
Swamp Thing. Much to their reluctance, they decide to look for
Harley Quinn to find out where the duo is hiding. However, Harley has gone off the grid since getting paroled. Batman leaves finding Harley to Nightwing while he figures out what the criminal duo are up to. At
A.R.G.U.S. Headquarters, Batman asks Sarge Steel about the kidnapping of a scientist named Dr. Harold Goldblum who has a background in chemistry, botany, and biological warfare. However, Sarge says they do not have any viable leads. Nightwing finds Harley working as a waitress at the Superbabes restaurant where waitresses are dressed as superheroes and supervillains. Tailing her, Nightwing asks where he can find Ivy and Harley says she is done with superheroes and supervillains and wants to live a normal life. Nightwing asks her why she is in skimpy outfits for minimum wage instead of using her psychiatric training. He angers her saying she has not reported to her parole officer in months and that he could drag her to jail. They fight until she knocks him out with a weak dose of Joker Gas. Meanwhile, Sarge shows Batman the home of Goldblum where he was kidnapped and Batman finds evidence that Floronic Man had been there. Nightwing wakes up and finds he has been tied to a bed. Harley shows him a pile of rejection letters and that her criminal past prevents her from getting rehired as a psychiatrist. Eventually, the two sleep together. Ivy is kissing Goldblum every six hours to control him with her pheromones. The criminal duo complain about humanity's negative environmental impact and Floronic Man says once their virus is activated every person on the planet "will have a vested interest in going green". Nightwing and Harley are tickling each other until Batman walks in on them with the result being that Harley decides to help. Batman has concluded the criminal duo are using Goldblum to replicate the process that turned Holland into Swamp Thing, but a virus version that will turn everyone into plant hybrids. Harley leads them to a popular hangout for henchmen. She gets the location of Ivy from her old minions Shrubby after having to perform
Blondie's "
Hanging on the Telephone". Then they had to fight their way past the henchmen on their way out. The trio head to
Blüdhaven where Ivy is saddened to see her friend helping Batman. Woodrue fatally wounds Goldblum to keep him quiet before he and Ivy escape as their lab catches fire. However, the dying Goldblum reveals that the duo is heading to Wainwright Swamp in
Louisiana where the correct chemicals are. Contacting
A.R.G.U.S., Batman, Nightwing, and Harley head after them to convince Ivy to stop her mad plans since they have the potential to kill all life on Earth. Harley resorts to crying to convince Ivy who is finally swayed by their relationship. Swamp Thing appears, informing Woodrue that he would threaten the Green with his concoction. However, he will not interfere. Batman and Nightwing wonder how to stop Woodrue until Harley points out he is a plant and asks if they have a match. Grateful, they both kiss her on the cheek and Batman sets Woodrue on fire. In a post-credits scene, Harleen Quinzel now has a reality television game show called "Ask Dr. Quinzel" where contestants run an elaborate obstacle course to win a year of professional therapy. ==Voice cast==