Samantha "Sam" Archer, her friends, and their "kindergarten buddies" are on a trip to the River City Children's Museum, which has been plagued by vandalism, and it is up to the sixth-graders and their new buddies to figure out who the vandals are and why they are set on closing the museum.

Kindergarten buddies -- At the museum -- Prime suspects -- A puddle problem -- Lunch time -- Lost buddy -- Mr. Kister -- The suspect list -- The vandal -- More museum mayhem -- Case solved.