During a fourth-grade field trip to Portwaller History Museum, Penelope fears that she is losing her best friend, Patsy Cline Roberta Watson, and decides to start her own secret museum so that she will never forget anyone important to her.
Having run away with her younger brother to live in the Metropolitan Museum of Art, twelve-year-old Claudia strives to keep things in order in their new home and to become a changed person and a heroine to herself.
Super-sleuth fourth grader Joe Sherlock must solve the disappearance of a four-thousand-year-old mummy's head from the town's Egyptian museum or Mr. Klopper will lose his job.
The Boxcar Children investigate when everything seems to go wrong for the Greenfield Museum as soon as the Museum displays a four-thousand-year-old ancient Egyptian mummy.