L'Improvisto is a suspenseful, effective drama by Alberto Lattuada about the careful planning and execution of a kidnapping. The "ringleader" and instigator of the clever plan is Tomas, a professor from a provincial town. His two cohorts are Claire (Anouk Aimée), his wife, and Juliette (Jeanne Valerie), his mistress. The trio make a rather different ménage à trois with objectives ranging far afield from the romantic. The circumstances of the preparation and carrying out of the deed keep tension coiled throughout.