In Gotham City, a new villain emerges: Mr. Freeze, who requires extreme cold to survive and is on a mission to freeze the city in order to save his cryogenically preserved wife. His plan hinges on his creation, a freezing gun capable of enveloping the city in ice. Mr. Freeze orchestrates a series of daring heists to gather the diamonds needed to power his weapon. Meanwhile, the dynamic duo, Batman and his partner Robin, are determined to stop Mr. Freeze's chilling plan and protect the city from his icy grip. Their relationship, however, is strained by trust issues and Robin's desire for more independence.

At the same time, botanist Dr. Pamela Isley is transformed into the seductive, nature-based villain Poison Ivy after a lab accident. She teams up with Mr. Freeze, aiming to eliminate humanity and allow plants to inherit the Earth, with the help of her mind-controlling pheromones that make men powerless to resist her. Amidst the rising tension with Mr. Freeze, Batman and Robin must also confront Ivy's manipulative charm, while an additional ally, Batgirl, joins the fray to assist in their efforts to save Gotham. The heroes' unity and resolve are tested as they tackle the dual threats presented by Mr. Freeze's cold calculations and Poison Ivy's venomous plans.