TORONTO — "Passchendaele" is an impressive feat for Canadian cinema.

With a $20-million budget that would barely cover the lead actor's salary on a U.S. studio blockbuster, Paul Gross -- who writes, directs and stars in the production -- manages to create a stunningly bleak landscape in which weary Canadian soldiers prevailed against a relentless German assault and a punishing rain.

Gross also manages to juggle smart, sober themes on the futility of war and heroic personal sacrifice without treading too heavily on the morality of armed conflict.

However, the film is ultimately undermined by heavy-handed religious imagery and an overly sentimental love story.

Set in October 1917, "Passchendaele" begins with the brutal bayonet slaying of a young German soldier, a scene drawn directly from a story Gross heard from his own grandfather.

Haunted by the killing, an injured Sgt. Michael Dunne (Gross) returns to a Calgary hospital tormented and conflicted by the blood he has shed in the name of valour.

Meanwhile, his nurse, Sarah Mann, played by Caroline Dhavernas ("Hollywoodland," "Wonderfalls") finds herself struggling to cope with a dark family secret and a foolhardy younger brother ("Train 48's" Joe Dinicol) eager to prove his worth through combat.

The tender relationship that develops between the scarred war hero and his troubled caregiver forms the main story arc of the film.

Despite offering a welcome respite from the harrowing violence that bookends "Passchendaele," the romance is hampered by a awkward and inexplicable exchange between the lovers, which they return to later in the movie.

The courtship ultimately bogs down the first half of the film, also undermined by a stagey portrait of wartime Calgary that comes across too much like a televised heritage moment.

Eventually, Dunne ends up returning to battle in order to protect Mann's asthmatic younger brother, but the two men find themselves caught up in the epic battle for Passchendaele.

The realistic portrayal of horrific conditions surrounding the harrowing assault is what saves the movie from a total descent into shmaltz.

Gross has come a long way since making his directorial debut with the 2002 comedy "Men With Brooms." In "Passchendaele," he admirably conveys the savagery of the trenches and the staggering disconnect between the battle's bullheaded military superiors and their haggard front-line troops.

Material on the historical drama has been sent to high schools across Canada as part of a nationwide media blitz, with some classes arranging field trips to see the film.

Rightly so. "Passchendaele" is a valuable depiction of one of Canada's most important battles.

Two and a half stars out of four.