The Conspiracy (Plot to Kill Hitler #1), Volume 1

Berlin, November 1943. Siblings Gerta and Max Hoffmann live a surprisingly happy life with their parents even though WWII rages on. Then one night, their neighborhood is hit by bombs and a mortally wounded man comes to their house, asking for Gerta and Max's father. Before the man dies, he hands over a packet of bloodstained documents and says, "For the sake of humanity, the Fuhrer must die!" And the children find themselves caught up in a fight between good and evil.