Matt's grandmother is celebrating her 80th birthday. His sister Cathy, who is only six, brags about the eight dollar present she has bought. Not to be outdone, Matt tells her that his present is going to cost a lot more. With only twenty-eight cents to his name and the birthday coming up in just a few days, Matt accepts his best friend Chris' offer for a dogsitting job. Chris' older sister takes care of other people's dogs on weekends. Without her knowledge Chris books a Pekingese named Jasper and hands him to Matt. Since Matt lives in an apartment building where no pets are allowed, he has to sneak Jasper into his room and keep his presence from his family. Now begins two nightmarish days - and nights - for Matt as the dog pees on the furniture, chews up Matt's new sneakers and turns Cathy's crayons into pulp. Then Cathy finds out about Jasper and blackmails Matt - his own sister, for pete's sake. But soon things get worse - much worse...