Six-year-old Moonee (Brooklynn Prince) and her mother Halley (Bria Vinaite) live in a budget motel run by Bobby (Willem Dafoe). Halley struggles to make the week-to-week rent by doing odd jobs such as selling branded perfumes on the streets. She soon gets desperate when she isn't making enough and resorts to desperate measures.
In the meantime, Moonee lives her life to the fullest, causing trouble wherever she goes. She makes new friends at the motel and gets them into scrapes as well. Looking at the world through Moonee's eyes, the film follows her journey during the summer days at the motel.