Jesse is an alien from another planet, convicted of political crimes and sent to Earth which is to serve as his "prison."  He is accompanied by a small floating robot, "Control," which is charged with guarding and supervising him as his parole officer.  Both are quickly adrift in a strange world with unfamiliar customs, and Jesse has to make his way through Earth (specifically Los Angeles), hoping for the day when his sentence is lifted (which will occur when he learns compassion) and he can return home.  Like most drifters that get their own TV series, Jesse finds himself each week embroiled with crooks preying on the innocent and ends up using his alien powers to help them.