ヴォルフスシャンツェ
Invited by General Henning von Tresckow, Stieff joined the German resistance in summer 1943. Taking advantage of being in charge of "Organisationsabteilung", he acquired and kept all sorts of explosives, including some from foreign sources. He provided the explosives for von dem Bussche's canceled assassination attempt on Hitler at the "Wolfsschanze" (Wolf's Lair) in November.