39 Clues Series 04
第四系列 Doublecross 两本书音频
Book #1 - Mission Titanic - Jude Watson
Book #2 - Mission Hindenburg - C Alexander London
Book #3 - Mission Hurricane - Jenny Goebel -January 26, 2016.（无音频）
Book #4 - Mission Atomic - Sarwat Chadda - June 28, 2016（无音频）
