Three disparate individuals with extraordinary abilities find their lives irrevocably intertwined in a tale that challenges the boundaries between heroism, villainy, and the extraordinary. David Dunn, a security guard with unbreakable skin and superhuman strength, is on a mission to use his powers for vigilance. He is on the trail of Kevin Wendell Crumb, a man with dissociative identity disorder who harbors 24 distinct personalities, the most dangerous of which is a superhumanly powerful entity known as The Beast. Their cat-and-mouse game leads to an encounter that results in both being apprehended by the authorities.

Both men are detained in a psychiatric facility where they meet Elijah Price, an intellectual with fragile bones and a complex understanding of comic book lore, who holds secrets about both Dunn and Crumb. The three are subjected to the studies of Dr. Ellie Staple, a psychiatrist specializing in individuals who believe they are superhuman beings. As she attempts to dissect and dampen their perceived delusions of grandeur, tensions escalate, and the line between delusion and reality begins to blur, setting the stage for a confrontation that threatens to redefine the nature of heroism and the potential existent within every human being.