A cocky Harvard graduate transports a load of marijuana from Berkeley to Boston. His girlfriend gets busted with the second load. He and a friend go against a dirty cop and a Cuban gangster to get the load and the girl back.

Peter is a cocky Harvard law student, who's tired of being square, so his best friend, theater director John, gets him into the drug business. Peter loves the excitement of the gig and agrees to transport a suitcase full of pot from his suppliers to him. As a fan of the Rolling Stones' song "Sympathy for the Devil," he picks Lucifer as his street name. At the drug dealers' hideout, Peter meets Susan and falls hard for her, since she's the complete opposite of his prudish, stuck-up, square girlfriend Annie. Susan likes him too and agrees to take him to a train station to hide the dope in one of the lockers there. They hit it off quickly. When they arrive at the station they notice a military officer, who's overseeing a funeral transport for what seems to be a casket of a dead soldier from Vietnam. This sight gives the two cold feet, so they leave to spend a night together at one of her musician friends' place. Peter then completes the job but soon asks John for another gig, since he really wants to see Susan again. However, this gig goes sour and the girl is busted with forty bricks (kilos) of marijuana by police sergeant Murphy, who happens to be a dirty cop in bed with Cortez, a dangerous Cuban gangster. John wants his dope back and Peter wants to save Susan, so they come up with a risky plan that eventually involves a round metal casing full of red heroin which everyone wants, and for which they would gladly kill.