The boarders are all suspicious of the mysterious Mr. Smith who lives behind door 16. Oscar Kokoshka moves in with Arnold when his wife, Susie, throws him out of their apartment following another fight.
Door 16: After a mysterious package is delivered at the boarding house, Arnold is entrusted to deliver the package to Mr. Smith, the most private boarder in the house. Unfortunately, the other boarders' curiosity is an obstacle Arnold must face. Arnold as Cupid: After Oskar and Suzie split up, Oskar lives with Arnold, and Arnold has to get them back together before Oskar drives him crazy.