The Math Inspectors--Stanley, Charlotte, Gertie, Felix, and Herman--take on another mystery during the Ravensburg Middle School's seventh grade field trip adventure to the old mining town of Forgotten, West Virginia. But it appears this old town is hiding more than a few secrets. And as usual, it will be up to The Math Inspectors to try and uncover them.

Its Christmas Eve in Ravensburg, and the town is bursting with anticipation for its oldest Christmas tradition. The annual opening of Douglas and Son's Toy Store, home of the greatest toys in the world, is finally here. But this is no ordinary Christmas Eve, and the surprise that awaits them is beyond any of their wildest imaginations: a surprise that threatens to ruin Christmas! Stanley, Charlotte, Gertie and Felix call in a little backup, but will...

"Stanley, Charlotte, Gertie and Felix are your typical twelve-year old kids. They love hanging out after school, they love burgers and milkshakes, and they love math. Wait. What? Oh, and one more thing. If there's anything they love more than math, it's solving mysteries. Thankfully, their hometown of Ravensburg, New York has plenty of mystery. Join these four friends in their hilarious adventures. Where there's always a little bit of math and a whole...

It's Christmas Eve in Ravensburg, and the town is bursting with anticipation for its oldest Christmas tradition.