Disaster awaits when the most annoying girl in school discovers the existence of our favorite tiny dinosaurs in the fifth installment of Dustin Hansen's illustrated chapter book series.

Vicky Van Varbles, AKA Lin's nemesis, AKA the most annoying person on the planet, has discovered the microterium! Lin is convinced that this is the Worst. Thing. EVER! Vicky has never kept a secret in her life. The only solution is to trap her in a bug jar for the rest of eternity.
But Danny has a different plan . . . if they can induct Vicky into the (newly created) International Microsaur Protection Agency, he's sure she can be convinced to keep their secret. But first Vicky has to pass Lin's increasingly difficult and dangerous tests . . . If Danny can't get Lin and Vicky to work together, then the microsaurs really might be doomed!