The fifth graders of Liberty Falls Elementary might be the worst fifth graders ever, but they still get to go on a field trip! They're going to visit the Edward Minks Mansion to learn about the eccentric inventor and founder of their town. Legend has it, there are some undiscovered inventions hidden in the house. The students are eager to find them, and they convince Principal Klein to let them out of writing their essay on Minks if they do.

But as Aaron, Eddie, Jessie, and Chloe explore the Minks Mansion, it seems like something strange is going on. Like the adults are missing and someone might be stealing the inventions. But in order to save the inventions and their teachers, the kids might just have to pull some serious pranks to stop the bad guys. Even if it means risking a lifetime of detention.

Can the fifth graders save their field trip and the mansion . . . or will this be the last field trip ever in school history?