When Joe Beck, a fifteen-year-old suburban kid, gets lost in a disreputable neighborhood on his way to an appointment in London, he is struck dumb by his first sight of beautiful and seemingly innocent Candy. She talks with him, teases him, but reveals nothing about herself except her phone number.

Later, they have a perfect day at the London Zoo, and soon Joe is as addicted to Candy as she is to heroin, in spite of the threats of her menacing pimp, Iggy. Almost nothing matters except his desire to free her from her terrible life—not his band's chance for a recording contract, not the song he has written for her that has become a hit without him.

But there is something that still matters to him, and when he rescues the young prostitute from her sordid rooming house and takes her into hiding to sweat out her addiction, Iggy finds and uses that one thing that is stronger than Joe's passion for Candy, in a heart-thumping, breathless conclusion.