Upon learning that the city has sold his neighborhood park to developers, fifth-grader Eric Clark determines to help his community by getting his mother elected mayor.
When thirteen-year-old Willy Wilson returns to Gloria to enroll in Gill Park Gallery School, he finds himself in the middle of a politically backed struggle to save the park and to solve a treasure hunt.
While spending the summer before seventh grade with his aunt, Willy Wilson finds his first friends ever in the colorful characters who all love the neighborhood park owned by an eccentric old man.