Based on the novel by L.P. Hartley, The Go-Between links the present and the past taking an ageing bachelor back to the long hot summer when he was twelve and lost his boyish heart to a beautiful, headstrong young woman who used his adoration to suit her own purposes.

Summer 1900: Leo is the guest of Marcus, a wealthy classmate, at a grand home in rural Norfolk. Leo is befriended by Marion (Julie Christie), Marcus's sister who is about to be engaged to Huge who is a viscount, however she has fallen in love with a handsome young tenant farmer (Alan Bates) who's class difference make an open affair unthinkable. She is unable to resist temptation though and sends messages to her lover to arrange a meeting through Leo, the go-between.