[7] In the spring of 1917 after the Battle of Vimy Ridge, Sergeant Michael Dunne of the 10th Battalion, CEF has survived heavy combat but suffers from neurasthenia.

David Mann (Joe Dinicol), Sarah's younger brother, is ineligible for military service due to asthma but is determined to enlist.

Dunne feels responsible for David's wellbeing and reenlists as a private under his mother's maiden name, McCrae, promising Sarah he will protect her brother.

Dunne's cover as McCrae is soon blown, but he manages to escape punishment and is promoted to platoon leader by Lieutenant Colonel Ormond, who knew him from earlier combat when his actions "should have got a V.C."

After the support company arrives, the 8th Battalion begins to withdraw from the battlefield, believing that they are finally relieved and leaving the job of holding the ground to Dunne's small force.

He is about to be shot when an artillery shell lands and the explosion throws him onto what is effectively a cross, created by walkway timbers and barbed wire from the trench.

When Dunne sees this he takes his helmet off, throws his gun down, and runs to David in a reckless attempt to keep his promise to keep him alive, being shot in the process.

The camera then pans out and the background alters to a field of hundreds of Canadian war graves with a riderless horse on the horizon.

The film was shot over a period of forty-five days and involved over 200 actors, some of them Canadian Forces soldiers with combat experience in Afghanistan.

Battle scenes were filmed on the Tsuu T'ina Nation reserve just outside Calgary, and principal photography finished in October 2007.

This film was inspired by Gross's relationship with his maternal grandfather, Michael Joseph Dunne, who served in the 56th, 5th, 14th and 23rd Reserve Battalions, CEF,[8] in the First World War.

In a rare conversation on a fishing trip,[9] Dunne told the story of bayonetting a young German soldier, who had eyes like water, through the head and killing him during a battle.

"[11]During the early portion of the film, the scene is recreated in a broken church, when Sergeant Michael Dunne bayonets a young German soldier through the forehead.

The story of Passchendaele pays tribute to a key event in our country's history, and will educate Albertans and all Canadians for years to come."

The Battalion was not scheduled to attack, but the CO wisely prepared his soldiers as if they would be making the main assault – a decision that paid dividends when the unit was called out of reserve.

Bingham argued the point to no avail, and watched with dismay as the mud-caked survivors of the 8th pulled out and slogged to the rear, leaving A Company to hold an entire battalion's frontage.