In the bustling streets of Gotham City, the relentless hero Batman (Val Kilmer) saves a security guard from the clutches of Two-Face, a devious villain who is the disfigured former district attorney Harvey Dent (Tommy Lee Jones). They find themselves locked inside a safe, which is perilously dangling from a helicopter and filled with acid. With a bit of ingenuity, Batman utilizes the security guard's hearing aid to unlock the safe just in time, narrowly escaping the resulting explosion from the Statue of Liberty.
Meanwhile, Edward Nygma (Jim Carrey), a researcher at Wayne Enterprises, is embarking on a dark journey after developing a disturbing device designed to transmit television signals directly into a person’s brain. When Bruce Wayne dismisses the invention due to its troubling implications, Nygma, driven by madness, tests the machine on his supervisor, resulting in death, and he subsequently resigns, leaving behind an enigmatic riddle that hints at his dangerous transformation into the Riddler.
As fate would have it, Bruce crosses paths with the intriguing psychiatrist Dr. Chase Meridian (Nicole Kidman). In an attempt to impress her, he invites her to a charity circus. Unfortunately, the festivities are interrupted when Two-Face and his henchmen attack, searching for Batman's secret identity. In the chaos, a family of acrobats known as The Flying Graysons meets a tragic fate at the hands of Two-Face, leaving only their youngest member, Dick, alive. Driven by vengeance and bravery, Dick throws a bomb into the river, managing to save lives but losing his family.
Bruce, taking pity on Dick, allows him to stay at Wayne Manor. However, he is soon burdened with the weight of Dick's desire to avenge his family. As he learns Batman's true identity, he pleads to join forces with Bruce, who, despite his reluctance, finds comfort in the wise counsel of his loyal butler Alfred.
On the other hand, Nygma has transformed into the Riddler and has formed a sinister alliance with Two-Face. He cleverly promises to unveil Batman's identity while sending Bruce increasingly cryptic riddles. With the commercial success of his mind-altering device known as the Box, Nygma gains not only wealth but also power, allowing him to tap into the mind of every user, including Bruce.
During a grand business gathering, Nygma's unveiled advancements lead him to discover Bruce’s secret. Chaos erupts when Two-Face attacks, almost burying Batman alive—only to be rescued by the determined Dick. In an effort to protect him, Bruce relinquishes his superhero mantle, opting instead to pursue a romantic relationship with Chase, who is unaware of the dangers her affiliation brings.
Disappointed by Bruce's withdrawal, Dick decides to leave but is soon plunged back into chaos when Two-Face and the Riddler invade Wayne Manor, shortly after Bruce reveals his secret to Chase. The Riddler wreaks havoc in the Batcave, capturing Chase and leaving behind a final riddle.
Utilizing his wits, Bruce deciphers the riddle and, realizing the dire situation, dons his surviving Batsuit. When Dick returns donning a costume fashioned by Alfred, he reveals his new identity as Robin, prompting Batman to finally accept him as a partner.
As they locate the Riddler's hideout, the duo faces trials that put their resolve to the ultimate test. Two-Face confronts Robin, while Batman fights to save both his young ally and Chase, who find themselves perilously suspended above a deadly pit. The Riddler, taunting Batman with impossible choices, underestimates the hero’s resourcefulness when Batman cleverly counters with a riddle of his own.
In a spectacular showdown, Batman saves Robin and Chase while orchestrating the downfall of Two-Face, leading to his unfortunate demise. The Riddler, now confined to Arkham Asylum, irrationally claims he is Batman, highlighting his descent into madness. Ultimately, Chase assures Bruce that his secret remains safe, sealing their bond with a kiss as she departs, leaving the uncertain future of Gotham hanging in the balance.
