It is off to Italy for Mimi and Papa and their two grandchildren, Christina and Grant. Mimi is writing a new mystery set in Italy. Papa is going to visit an old friend. It does not take long for a mystery to unfold as Christina discovers a puzzling advertisement in an Italian newspaper. Christina, Grant and their two new friends Luigi and Francesca look for clues while exploring Italy on fast scooters and floating gondolas. The kids get caught up in the middle of Carnivale holiday festivities as they solve the crime.