Cary Grant stars as Jerry Flynn, a financially-strapped producer who is besieged by creditors and desperate for something to save his Broadway theater. Flynn thinks he may have found just what he's looking for in Pinky Thompson (Ted Donaldson), a nine-year-old boy whose caterpillar, Curly, dances to the tune of "Yes Sir, That's My Baby." Despite the fervent objections of the boy's lovely older sister (Janet Blair), he lures Pinky into cutting a deal, only to have second thoughts after realizing that he has stooped to cheat a child. But when Curly disappears, a futile search leaves Pinky inconsolable until a beautiful butterfly answers Flynn's musical call.