The boy in question is named David and he is a young and shy teenager who doesn't have many friends. One day, while wandering the streets, he stumbles upon a pack of rats in an alleyway. As he watches them, he spots one rat that seems different from the others - bigger, smarter and more aggressive. This is Ben, the leader of the pack.
Despite his initial fear, David finds himself drawn to Ben and begins to take care of him, bringing him food and shelter and even communicating with him. As their friendship grows stronger, David discovers that Ben and his pack of rats are responsible for a series of brutal killings in the city, much to his horror.
As the authorities close in on the killer rats, David faces a difficult choice - does he betray his friend Ben and turn him over to the police, or does he stand by him and risk being hunted down alongside the murderous rodents?
The film Ben was released in 1972 and was directed by Phil Karlson. It starred Lee Montgomery as David, with Meredith Baxter and Joseph Campanella in supporting roles. The film was a sequel to the 1971 thriller Willard, which also featured killer rats as the primary antagonists.