He joined the resistance and acted as a secret liaison between Tresckow in Russia and Ludwig Beck, Carl Goerdeler, Hans Oster, and Friedrich Olbricht in Berlin, taking part in various coup d'état plans and plots. On 13 March 1943, during a visit by Adolf Hitler to Army Group Centre Headquarters in Smolensk, Schlabrendorff smuggled a time bomb, disguised as bottles of Cointreau, onto the aircraft which carried Hitler back to Germany. The bomb detonator failed to go off, however, most likely because of the cold in the aircraft luggage compartment. Schlabrendorff managed to retrieve the bomb the next day and elude detection. Schlabrendorff was arrested following the failed 20 July Plot. He was sent to Gestapo prison where he was tortured, but refused to talk. While imprisoned he met fellow imprisoned co-conspirators Wilhelm Canaris, Hans Oster, Ulrich von Hassell, Johannes Popitz, Carl Goerdeler, Josef Mueller, and Alexander von Falkenhausen. He was brought before the Nazi People's Court on February 3, 1945. However, while Schlabrendorff was awaiting trial, the courtroom took a direct hit from a bombduring an American air raid led by Lt. Col. Robert Rosenthal. The bomb killed Judge-President Roland Freisler, who was found crushed by a beam, still clutching Schlabrendorff's file. Schlabrendorff did not escape, however, and was arraigned before the court again in March, now headed by Nazi lawyer Wilhelm Crohne. Following an intense defence, conducted by himself on both legal and procedural grounds and in an exceptionally rare instance in its final nine months of existence, the People's Court acquitted von Schlabrendorff. His death was later demanded by Hitler's decree, but the order was defied insofar that it was never carried out. After his second trial, Schlabrendorff was moved from one concentration camp to another: Sachsenhausen, Flossenbürg, Dachau, Innsbruck. In late April 1945 he was transferred to Tyrol together with about 140 other prominent inmates of the Dachau concentration camp, where the SS-Guards fled after being confronted by a regular German Wehrmacht unit led by Wichard von Alvensleben. He was eventually liberated by the Fifth U.S. Army on 5 May 1945.
He married Luitgarde von Bismarck, born at Frankenstein in Silesia on 12 May 1914, and had the following children:
Herzeleide von Schlabrendorff, married to Andreas Stökl, four children.
Dieprand Ludwig Carl Hans-Otto von Schlabrendorff, married to Eva von Polenz, one child.
Jürgen-Lewin Hans von Schlabrendorff, married to Beate Everth, and had two children.
Fabian Gotthard Herbert von Schlabrendorff, married to María de la Cruz Caballero y Palomero, two children.
Maria von Schlabrendorff, married Christian Eick, three children; married to Gottfried von Bismarck.
Carl Joachim Henning von Schlabrendorff, married to Mechthild von von Hülst, with two children.
Quote
"To prevent this success of Hitler in all circumstances and by all means, even at the expense of a heavy defeat of the Third Reich, was our most urgent task. " - from his book, Offiziere gegen Hitler , Zurich: Europa-Verlag, 1946, p. 38.
Books
Schlabrendorff, Fabian von "Offiziere gegen Hitler", Fischer Bücherrei, FRG 1959