A washed-up superhero movie star named Riggan Thomson attempts to reinvent his career by writing, directing, and starring in a Broadway production. Riggan struggles to escape the shadow of his iconic role as Birdman, a character that continues to haunt him in both literal and metaphorical ways. Challenged by an egotistical method actor, a difficult daughter, a concerned ex-wife, and a skeptical producer, Riggan faces a mounting pressure to ensure the play's success. His internal battle manifests through surreal experiences, blurring the lines between fantasy and reality, as he grapples with his identity, family, and the demands of artistic expression.

As the opening night approaches, Riggan's tumultuous journey intensifies. The production is beset with catastrophes, including actors getting injured and replaced by the unpredictable Mike Shiner, who quickly asserts his dominance on stage and off. Riggan's daughter, Sam, a recovering addict working as his assistant, highlights his irrelevance in the modern world, exacerbating his fears of failure. Throughout the chaotic process, Riggan must confront the truth about his motivations for the play and come to terms with the man he is versus the man he wants to be. The boundaries of stage and life converge in a whirlwind of drama, comedy, and existential angst, propelling Riggan towards a climactic opening night that could either redeem or destroy him.