There's a mystery at Washington Middle School that only Michael the wildlife detective can solve. Secretive guests have moved into the school gymnasium and Principal Green doesn't know what to do. But not to worry! Using math, music, science, and physical evidence, Michael uncovers the identities of the mysterious intruders who have decided to make the school their new home.

As Michael reveals clue after clue, young readers will enjoy guessing the identities of the critters putting the school into an uproar. Throughout his stakeout, Michael offers a lesson on the gymnasium's new residents and how to safely and humanely encourage them to move along.

Author Michael Birt, a wildlife biologist, shares with readers the importance of treating wild animals and nature with respect and kindness--even when they end up in unnatural spaces and cause inconvenience for their human neighbors. He highlights the importance of finding compassionate solutions to pesky problems and explains why the school's mystery guests are so special.