Oster Conspiracy

The Oster Conspiracy of 1938 was a proposed plan to overthrow German Führer Adolf Hitler and the Nazi regime if Germany went to war with Czechoslovakia over the Sudetenland. It was led by Generalmajor Hans Oster, deputy head of the Abwehr and other high-ranking conservatives within the Wehrmacht who opposed the regime for behavior that was threatening to bring Germany into a war that they believed it was not ready to fight. They planned to overthrow Hitler and the Nazi regime through a storming of the Reich Chancellery by forces loyal to the plot to take control of the government, who would either arrest or assassinate Hitler, and restore the exiled Wilhelm II as Emperor.

The plot was organised and developed by then Oberstleutnant Hans Oster and Major Helmuth Groscurth of the Abwehr. They drew into the conspiracy such people as Generaloberst Ludwig Beck, Generaloberst Walther von Brauchitsch Generaloberst Franz Halder, Admiral Wilhelm Canaris, and Generalleutnant Erwin von Witzleben. The working plan was for Count Hans-Jürgen von Blumenthal to lead a storm party into the Reich Chancellery and kill Hitler. It would then be necessary to neutralize the Nazi Party apparatus in order to stop them from proceeding with the invasion of Czechoslovakia, which they believed would lead to a war that would ruin Germany.

...
Wikipedia