#13. Snowbound mystery -- #14. Tree house mystery -- #15. Bicycle mystery.
Read by Tim Gregory and Aimee Lilly.
Snowbound mystery : It's an unusual winter vacation for the Alden family when a huge snowstorm traps them in the wood! Tree house mystery: The Alden children are helping their neighbors build a tree house. Bicycle mystery : The Alden's are making the journey to their Aunt Jane's house on an overnight bicycle trip.