In the introduction, Michael's family is searching for secrets while attending a party. They are the spies for the Allies in world war II, in Berlin
The three main charter in the book is Michael and his friend Fritz, and Simon. Simon is an army his plane crashed into the ground, and Michael and Fritz saw it, so Michael bring Simon home.
After Simon went to Michael's home. Simon says that the German is making a jet call projekt 1065, and Fritz says that he also saw his dad is doing this in his lab.
Fritz wants to join the SRD, this is a German army, so Michael and Fritz both go to the camp to join the army, the way to get in the SRD is everyone has to do some challenge the first challenge for them is to fight on the stage, so they fight each other Michael wins the fight. Then both of them get in the SRD
Fritz carrying a bomb all the time. on the roof of the train, it detonates on the mountain to trigger an avalanche.