When their mother goes on a vacation to Hong Kong, two mischievous siblings are sent to stay with their boring grandfather (David Niven). The children come across two inept criminals (Don Knotts and Darren McGavin) and get a bright idea: They'll have themselves kidnapped. Certain that their plan will bring their mother back from her holiday, the kids proceed with their plan and manage to ruin the lives of their "captors" in the meantime.