Lost Our Lisa.When Bart comes home with some novelty items superglued to his face, Marge takes him to the emergency room, spoiling Lisa's chance to go the Springfield Museum to catch the last day of the Isis Exhibit. Marge forbids Lisa to take public transportation to the museum by herself, but Lisa is able to manipulate her father for his permission to take the bus. However, Lisa takes the wrong bus and ends up in the middle of nowhere. Meanwhile, Homer realizes that he should not have given Lisa permission to take the bus by herself. He rushes to the museum to find her, but she has managed to get downtown after much travel. Near the museum, Homer decides to use a cherry picker to locate Lisa, but the cherry picker loses control and falls into the pier, and floats off to a drawbridge. Lisa sees this, and quickly tells the bridge operator to lower the bridge, which catches Homer by his head to save him. The exhibit is closed, but Homer promises to break into the museum at night with Lisa, where the two discover one of the exhibits' objects is a musical box.