A highly unlikely crime helps bring together two brothers in this nostalgic comedy drama. Rocky Plumm (Owen Pearce) is a five-year-old boy growing up in a small Montana town in the mid-'60s. In Rocky's eyes, there's no star bigger or brighter than local kid's show host Happy Herb (Henry Winkler), who appears on TV weekday afternoons with his puppet friend Froggy Doo. When the Froggy Doo puppet is stolen, Happy Herb's show goes off the air until the doll can be found, which only adds to Rocky's unease as his folks (William Baldwin and Lisa Guerrero) struggle to salvage their clearly failing marriage. Rocky's big brother, Elliott (Chris J. Kelly), isn't especially concerned about Happy Herb's problems or the forced hiatus of Rocky's favorite show, but when Haley (Morgan Flynn), a pretty girl with a yen for detective stories, moves in next door, he suggests they join forces to help find Froggy Doo. Before long, the youthful sleuths find themselves crossing paths with a pair of federal agents (Peter Scolari and Rick Overton) and a growing list of suspects as they follow the thief's trail. A Plumm Summer was the first feature film from writer and director Caroline Zelder.