Of the 15 known assassination plots hatched against Adolf Hitler by anti-Nazi resisters in Germany, the most ambitious one was mounted by senior German army officers and dissenting politicians on July 20, 1944.

Tom Cruise as Col. Claus Schenk Graf Von Stauffenberg

Had they succeeded, the course of history may well have changed. Alas, the plot failed, and one of the key participants, Col. Claus Schenk Graf von Stauffenberg, was summarily executed by a vengeful Nazi regime.

Bryan Singer’s historical thriller, Valkyrie, which is currently playing in Toronto, is based on these events. Singer has made an earnest effort to recreate the plot, which almost succeeded, and Valkyrie is a workmanlike account of it.

The two-hour film, starring Tom Cruise as the heroic Von Stauffenberg,  unfolds in three distinct phases.

It opens in 1943 in the bright sunshine of the Tunisian desert, where Von Stauffenberg – an outspoken officer who has qualms about Germany’s military strategy in North Africa – is posted.

Von Stauffenberg’s command car is strafed by an Allied bombing raid and he is severely injured, losing his right hand, left eye and two fingers on his left hand.

The movie shifts to Germany, where Maj.-Gen. Henning von Tresckow (Ken-neth Bra-nagh) tries to assassinate Hitler by placing a bomb inside a wine case aboard Hitler’s personal aircraft.

The device fails to detonate, forcing von Tresckow to go back to the drawing board. He recruits Von Stauffenberg, a Catholic from an aristocratic family. Von Stauffenberg joins the German resistance movement because he is appalled by Germany’s treatment of civilians, including Jews, in Nazi-occupied areas and wants to save his country from certain defeat.

In this segment, the plotters abort a plan to kill Hitler, because SS chieftain Heinrich Himmler has surprisingly not shown up at a meeting.

Cruise, stiff and correct in an army uniform and a black patch covering one of his eyes, portrays Von Stauffenberg with militaristic precision in a plausible performance. That he and the other actors deliver their lines in American and British-accented English is definitely not off-putting.

The last part of the film turns on the explosion that slightly injured Hitler (David Bamber) in his secluded compound in East Prussia and on Hitler’s wrath and payback.

Singer, whose films hum with energy and purpose, elicits fine performances from an accomplished cast that includes Bill Nighy, Terence Stamp, Kevin McNally  and Christian Berkel as four of the anti-Nazi dissenters and Carice van Houten as Von Stauffenberg’s loyal wife.

Valkyrie stands as a cinematic monument to a plot that would have had incalculable consequences, both on World War II and the Holocaust, had it been successful.