The Beindorf family, consisting of Ned, Janet, Grover, and Stacy, live a supposedly happy typical family life in the
suburbs of
Defiance, Ohio. In fact, Ned and Janet are not happy and are
separating, although they tell Grover and Stacy it is not a
divorce. Grover and Stacy first try to recreate Ned and Janet's
honeymoon in
Hawaii in the basement, but this fails to bring any happiness into their relationship. Grover and Stacy then leave the basement, telling Ned and Janet they must get another surprise for them upstairs. They go up, close the door, and nail it shut. They vow to keep it so until Ned and Janet work out their problems and get their marriage back on its feet. The next day, Grover tells his best friend, Matt Finley, what he has done and T.J. Krupp, the wealthy local bully, overhears them. Matt goes over to the Beindorfs' house to look at Grover and Stacy's work and is impressed. T.J. shows up to have a look and actually installs a newer, more secure door to keep Ned and Janet trapped inside. T.J. and Matt then leave to collect their parents and bring them there to lock them up as well. Matt's father, Vic, never keeps a wife for more than two years and is on his latest one, Louise. T.J.'s father, Donald, does not treat his wife, Gwenna, well. Matt also brings his bulldog, Cosmo, and two younger brothers, Jimmy and Teddy, who come armed with sleeping bags and T.J. brings his boa constrictor, Spot. When Grover asks what is going on in response to his friends setting up camp at his house, T.J. says, "Our parents could be down there for months!" Ned and Janet almost talk Grover into letting them out, but Donald threatens him with legal action. Grover finds out that his crush, Brooke Figler, is also having parental problems: her mother, Cindy, acts awkward, going so far as to trying to hang out with her friends. Grover invites her to lock Cindy up with the rest. The children begin to help their parents solve their problems. They try to find a way out of the basement while getting along and seeing what each of their problems are. The children also work out their differences with each other above. They eventually give in and up to the
police led by Chief Rocco. Their parents are set free. Some time later, Ned and Janet reconcile and took a second honeymoon to Hawaii. Vic and Louise's marriage lasts past the two-year mark and they are expecting another child. Donald and Gwenna get divorced, though she later goes back to law school and they open up a law firm together. Cindy starts dating other guys instead of intruding on Brooke's dates. Also, Grover and Brooke became a couple and she passionately kisses him in front of their classmates at school. He concludes that if Ned and Janet ever try to get divorced again, he might think of locking them in the attic. ==Cast==