Mike (John Moulder-Brown), a 15-year-old bathhouse worker, develops a crush on his older, attractive co-worker, Susan (Jane Asher). At first they help each other secure bigger tips by swapping their respective male and female clients. But their tidy business arrangement is severed when Mike discovers that Susan has not only shunned him, but is cheating on her fiancé with an older swim coach. As Mike begins stalking Susan in an effort to break them up, his innocent crush spirals into obsession.