Billy has a fabulous new tree house - complete with elevator - and all the kids want to play in it. However, when Billy refuses to let Old Tom in, Lucy decides to build her own with rubbish from the tip. Meanwhile, the other kids aren't having much fun because Billy is being too fussy about his new tree house. But when they try to leave, they get stuck in the lift. Old Tom and Lucy, on their way home from the tip, see the drama. Old Tom rescues the kids but accidentally destroys the tree house. So they all go back to Lucy's place and build a new one.