In late 1980s New York, a theater artist living with AIDS takes on one possibly last great role.

An 18th birthday mushroom trip brings free-spirited Elliott face-to-face with her wisecracking 39-year-old self. But when Elliott’s "old ass" starts handing out warnings about what her younger self should and shouldn't do, Elliott realizes she has to rethink everything about family, love, and what's becoming a transformative summer.