Robert E. McEnroe's whimsical Broadway play The Silver Whistle was adapted to suit the talents of Clifton Webb in Mr. Belvedere Rings the Bell. It all begins when "super genius" Lynn Belvedere (Webb) briefly halts a lecture tour to bring some happiness into the lives of a gloomy senior citizens' home. To gain entry into the establishment, the virile, fiftysomething Belvedere claims to be 77 years old. The rest of the inmates are invigorated by the presence of so youthful a "septuagenarian," and before long everyone has taken a new lease on life. Belvedere also finds time to smooth the romantic path for Reverend Watson (Hugh Marlowe) and his fiancée Miss Tripp (Joanne Dru). When Mr. Belvedere's subterfuge is found out, the residents are momentarily dismayed, until they realize all the good their visitor has done. With Clifton Webb in charge (and with an able assist by supporting player Zero Mostel as Belvedere's business manager), Mr. Belvedere Rings the Bell is never as treacly or maudlin as it might be under different circumstances. Future Ward Cleaver Hugh Beaumont shows up unbilled as a cop in the opening scene.