While searching for her friends at the Dino Festival, Clementine Wim runs into two people carrying what she thinks is the Tiled Lunch Counter (a famous painting) away from the Capitol City Art Museum, but when she checks the painting is still hanging in place--and before she can track down the thieves, and prove that the painting now in the museum is a forgery, she has to convince her friends that she was not imagining things.

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.

While their sixth-grade class is on a field trip to Everglades National Park, James "Gum" Shoo and his friends find a suspicious park ranger and a gang of poachers.

The Haunted House ride at Fun City is rumored to be haunted by the ghost of someone who died there, and when Samantha "Sam" Archer and her friends get trapped inside they need to find the truth.

As Independence Day approaches, Raining Sam and his friend Amal see what they think is the ghost of a soldier lurking around an exhibit on the Vietnam War, after hours at the Capitol City Museum of American History--and he and his friends from the other museums are determined to find out what (or who) is behind the haunting, and why they are doing it.

When the spacesuit of famous astronaut Sally Ride disappears from a traveling exhibit, Amal Farah, daughter of the Air and Space Museum's archivist, and her three friends, are determined to find the culprit before the exhibit is cancelled.

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 the Franklin Middle School's sixth grade arrives at the amusement park, they find that the electronic cards that serve as all purpose tickets and game trackers have disappeared, so Sam, Egg, Gum, and Cat set out to solve the mystery and save the class field trip--and it is up to the reader to determine the course of their investigation.

When the class bully disappears on a field trip to the River City Zoo, James Shoo, known as "Gum" and the other sixth-grade detectives are determined to find out what happened, and it is up to the reader to choose what direction their investigation will take.

While cleaning up their great-great-uncle's house in preparation for selling it, thirteen-year-old Roy and his eleven-year-old brother, Jason, find two strange little doors and learn that someone is trying to open them to get what lies between.