Into these women's lives comes an innocent teenage girl named Dinah (series star Rachel Skarsten), who is drawn to the clock tower by powerful, haunting visions. Unsure of her background but impressed by her budding metahuman powers, the two crimefighters allow Dinah to help them thwart a criminal scheme that has resulted in several mysterious suicides and threatens the city's infrastructure. The mastermind behind the mayhem is Dr. Harleen Quinzel, with whom Helena undergoes court-ordered therapy, unaware that she is actually villain Harley Quinn (series star Mia Sara), a brilliant madwoman who was the paramour of The Joker (voiced by Mark Hamill). Dreaming of creating a criminal empire, Harley plans to release all the lunatics from mental institutions and use the resulting chaos to take control of New Gotham.
Meanwhile, a policeman, Detective Jesse Reese (series star Shemar Moore), who possesses a dark secret of his own, goes on a personal mission to figure out what's happening in New Gotham and who the mysterious Helena Kyle really is.