When a priceless sculpture disappears from the Capitol City Art Museum, thirteen-year-old Clementine Wim, daughter of an assistant curator, and her three friends set out to solve the mystery and recover the Statue of Gudea.
When the plans for the Bat-Wing, a historical aircraft, disappear from the Capitol City Air and Space Museum, eleven-year-old Amal Farah's father is blamed, and it is up to the four young friends to solve the mystery and save her father's job.
When a series of accidents and other strange happenings at the Capitol City Natural History Museum lead to rumors that the museum is being haunted by the ghost of a Pterosaur, ten-year-old Wilson Kipper and his friends set out to solve the mystery.
Somebody is vandalizing exhibits at the Capitol City Museum of American History, and it is up to twelve-year-old Raining Sam and his friends to find the culprit before irreparable damage is done.