Intellectually precocious teenager Lauren King lives in Paris with her somewhat ditzy mother. On a movie set, she strikes up a friendship with teenage film buff Daniel Michon. After Lauren's mother forbids her to date the outspoken Daniel, the young lovebirds team up with eccentric pickpocket Julius to run away to Venice, where, according to legend, a couple who kiss under the Bridge of Sighs will stay together forever.

Laurence Olivier
as Julius

Diane Lane
as Lauren King

Thelonious Bernard
as Daniel Michon

Arthur Hill
as Richard King

Sally Kellerman
as Kay King

Broderick Crawford
as Brod

David Dukes
as George de Marco

Andrew Duncan
as Bob Duryea

Claudette Sutherland
as Janet Duryea

Graham Fletcher-Cook
as Londet