Jimmy Stewart stars as San Francisco police detective “Scottie” Ferguson who leaves the force after witnessing a fellow officer fall to his death and thereafter suffering from acrophobia – an unsettling fear of heights, accompanied by the dizzying sensation of vertigo. When an old friend asks Ferguson to do him a favor and follow his strangely-behaving wife Madeleine. He does so and becomes embroiled in a complex murder scheme that culminates in him having to face his deepest fears.