In the 1940s, Baby Jane Hudson Lynn Redgrave is a world-famous child star who dominates her shy sister Blanche Hudson Vanessa Redgrave, who, as Jane's understudy and stunt double, longs to carve out an acting career of her own. By the 1960s, Blanche has matured into a serious, celebrated actress, while Jane's star has dimmed into obscurity. A tragic car accident paralyzes Blanche from the waist down and lands Jane in a psychiatric hospital. Everyone believes Jane, consumed by jealousy, rammed the car and then spiraled into guilt-wracked madness.
In the present, the aging sisters share a crumbling Brentwood mansion, where Jane still clothes herself in Baby Jane’s old outfits and makeup to care for a paraplegic Blanche. Blanche’s films reappear on home video, sparking a modest comeback that rekindles the tension between the two sisters. Jane resents Blanche’s renewed attention and begins a campaign of vicious pranks, intercepting mail and constantly reminding the world—and Blanche—that any success Blanche enjoys rests on Jane’s past glory. Blanche and her physical therapist, Dominick Bruce A. Young, worry that Jane’s cruelty could turn violent if Blanche tries to secure their future without her.
Desperate for a return to relevance, Jane visits a video store and encounters Billy Korn John Glover, the owner who offers to manage her comeback for a cut of the proceeds and promises a spot in a talent show. Jane agrees, not realizing Korn’s real motive is financial gain and manipulation. At home, Blanche attempts to call her psychiatrist, but Jane overhears and violently confronts her. Blanche tries to escape but Jane locks her upstairs, leaving her bound and unable to communicate. Starved and desperate, Blanche finds evidence of Jane forging signatures on checks to drain her funds. When Dominick arrives for therapy, he discovers Jane has bound Blanche with duct tape and, in a desperate struggle, Jane stabs Dominick to death and hides his body in the basement screening room.
The supposed “talent show” Korn has lined up turns out to be a drag revue, with Korn himself costumed as Blanche. When the two sisters attempt a duet from their childhood, the crowd mocks Jane for her appearance and weak singing, and she suffers a fresh breakdown, forced offstage. Korn races to the mansion and finds Blanche near death; Jane retaliates by stabbing Korn with a broken trophy. With Blanche dying, Jane drives them toward the beach—their childhood sanctuary—where Blanche finally confesses that she was driving the car the night of the accident and let Jane take the blame. The police arrive as Blanche lies unconscious, and Jane, overwhelmed by guilt and warped feeling of self-preservation, walks into the sea. A police officer pulls her from the water, and the final image lingers on Jane’s smiling face as she goes willingly with the authorities.
