Nancy, Bess, and George can't wait to check out Flutter House, an awesome new museum that's all about butterflies! The girls are thrilled when they get to see the beautiful creatures up close and personal.

But soon after their class leaves, the rarest butterfly, a Blue Morpho, goes missing! It's up to the Clue Crew to get the valuable butterfly back safely. But with a long suspect list and not many clues, it's going to be a tough case for Nancy and her friends.