Professor Lichtwitz, a successful architect and notorious womanizer, secretly accesses his penthouse via his office. Employee Bodo, assuming Lichtwitz is away, invites dentist’s assistant Stella to the “vacant” penthouse for dinner. Unaware of his boss’s return, Bodo and others, including Lichtwitz’s wife, believe the penthouse is empty, triggering a hectic swirl of mistaken assumptions and visitors.