Much of the first part of the novel details how Claudia and Jamie settle in at the museum : blending in with school groups on field trips during the day to get a free presentation , hiding in the restroom at closing time to stay there , and emerging at night to bathe in the fountain and sleep on antique beds . Much of the early part of the novel details how Claudia and Jamie settle in at the museum : blending in with school groups on field trips during the day to learn more about the museum 's exhibits , hiding in the bathroom at closing time to avoid the staff checking to make sure that all the patrons have left the museum , bathing in the fountain , picking up `` wishing coins '' , and sleeping on antique beds .