A new infection that simply makes people feel happy is treated as a threat by the authorities while its "victims" work to spread it to others.
George Peppard
as Pete
Mary Tyler Moore
as Liz
Dom DeLuise
as J. Gardner Monroe
John McMartin
as The Mayor
Nathaniel Frey
as Conrad
Charles Lane
as Dr. Shapiro
Jeanne Arnold
as Gertrude
George Furth
as Murgatroyd
Morty Gunty
as Sgt. Gunty
Joe Ponazecki
as Officer Ponazecki
Frank Campanella
as Captain Wallace
Susan Saint James
as Aida
