World famous detective Philmore Harty calls on his sons, the equally world famous Harty Boys, to help him investigate a robbery at the Minneapolis Institute of Arts. All the clues point to one suspect, Philmore Harty's old nemesis The Platypus! But when The Platypus declares his innocence, the Harty Boys believe the case might not be so open and shut after all! Can the clues be trusted? Will the forensic evidence collected by the Harty Boys' mom, maybe not world but nationally or at the very least regionally famous criminologist Lana Harty, shed any light on the case? Why won't the Harty Boys' brainy chum Becca make the boys lunch? Who is the mysterious new kid in town? And what does Nelson Filtch, evil founder of the Gluten Free Liberation Army, have to do with anything? Never fear, boys and girls! The Harty Boys will discover the answers to all these questions--and do it in time for dinner!