Carole Marsh

Grant spots a big problem with Big Ben-- and he and his sister, along with their two new best friends, George and Maggie, take a whirlwind tour from the top of the Eye, up the Thames River, down into a dungeon, and more-- in search of clues to solve The Mystery of Big Ben.

Mimi, Papa and two of their grandchildren - Christina and Grant - fly to Paris aboard Pap's red and white airplane, The Mystery Girl. They find a famous statue is missing from the Louvre Museum and the Eiffel Tower is in danger of falling.