Around the world in 80 mysteries

Christina and Grant have an adventure involving a mysterious map while visiting Neuschwanstein Castle in Bavaria, Germany, with their grandparents during Oktoberfest.

Mimi, who is fond of writing about mysteries, travels to Antarctica with her Papa, Christina, and Grant to search for the cause behind some penguins that have gone missing, and though they receive a warm welcome, not everyone is happy with their arrival.

Christina, Grant, and their new best friends, George and Maggie, explore London together as they try to solve the mystery of Big Ben.

Christina and Grant encounter mysteries while visiting Japan which take them from Tokyo to Mount Fuji.