Evelyn is a Chinese American immigrant who runs a laundromat with Waymond. Tensions are high: the laundromat is being audited by the IRS, Waymond is trying to serve Evelyn divorce papers, Evelyn's demanding father Gong Gong^[a] has arrived from Hong Kong, and Evelyn's lesbian daughter Joy wants her mother to accept her non-Chinese girlfriend, Becky.

At a fractious meeting with IRS inspector Deirdre Beaubeirdre, Waymond's body is briefly taken over by Alpha-Waymond, a version of Waymond from the "Alphaverse". Alpha-Waymond explains to Evelyn that many parallel universes exist as every life choice creates a new universe. The Alphaverse, led by the late Alpha-Evelyn, developed "verse-jumping" technology enabling people to access the skills, memories, and bodies of their parallel-universe selves by performing bizarre actions. The multiverse is now threatened by Jobu Tupaki, the Alphaverse version of Joy. Her mind was splintered after Alpha-Evelyn pushed her to extensively verse-jump. Jobu now experiences all universes at once and can verse-jump and manipulate matter at will; she has created a black hole-like "everything bagel"^[b] that threatens the multiverse.

Evelyn is given verse-jumping technology to fight Jobu's verse-jumping minions, now converging on the IRS building. She learns of Waymond's plans for divorce. She discovers other universes where she made different choices and flourished, such as becoming a kung fu master and Chinese movie star (and where Waymond is a successful businessman). Alpha-Waymond believes Evelyn, as the greatest failure of all Evelyns in the multiverse, has the untapped potential to defeat Jobu. Alpha-Gong Gong instructs her to kill Joy to stop Jobu from entering her universe, but she refuses. She decides to face Jobu by gaining powers that she earns by repeatedly verse-jumping while chased by Jobu's minions and Alpha-Gong Gong's soldiers. Jobu locates and kills Alpha-Waymond in the Alphaverse. As Jobu approaches Evelyn, Evelyn's mind splinters and her body falls lifeless.