It's the fall of 1985 in Palo Alto, California. Phil (James Franco, 127 HOURS, SPIDER-MAN), a divorced father, takes his two young boys to Yosemite National Park. During the trip, there is a radio warning about a mountain lion that has found its way into their suburban hometown of Palo Alto, where it has attacked several children. There is a looming sense of doom in the wilderness as Phil's oldest son, Chris, stumbles upon what appears to be a human rib cage. Back in Palo Alto, a second boy named Joe is bullied by one of his classmates, Ted, a stocky boy. Bullied in school while also grieving for the loss of his brother, Joe befriends the much older Henry (Henry Hopper, RESTLESS) who helps to temporarily fill the void left by his brother by reading comic books together. One day after school, the three 5th grade boys (Chris, Joe and Ted) decide to go on an adventure and hunt the mountain lion that has been terrorizing their community. They bring a loaded gun that was found in Chris' home. This bonding journey will change their lives forever, coming back transformed from the experience. Based on stories from James Franco's book "A California Childhood".