Contains spoilers for this episode.
Yorkie arrives at Tucker's nightclub in what appears to be 1987 and meets Kelly, whose confidence draws her onto the dance floor. Yorkie initially retreats, saying she is engaged. The following week they become lovers, but Kelly then disappears from the places Yorkie expects to find her. A suggestion to try another time sends Yorkie searching through different decades until she locates Kelly again and asks why she has been avoiding her.
San Junipero is a simulation that lets elderly visitors inhabit younger bodies and allows the dead to remain permanently. Kelly is dying, while Yorkie has spent decades paralysed after a crash following her parents' rejection of her sexuality. Yorkie wants to be euthanised and uploaded, but her family refuses consent. Her planned marriage to nurse Greg would provide permission. Kelly visits her in the physical world and offers to marry her instead.
Kelly authorises Yorkie's death, and Yorkie begins living in San Junipero without the limits placed on temporary visitors. She asks Kelly to join her. Kelly initially refuses because her husband declined uploading after their daughter died before the system existed. Their argument leaves Yorkie alone again when Kelly's visiting time expires. As her illness worsens, Kelly changes her decision. Her body is buried with her family, while she reunites with Yorkie in the town, where their stored minds can share the life they have chosen.