Everything you ever imagined about the characters of John Wayne and Montgomery Clift in "Red River" or Joel McCrea and Randolph Scott in "Ride the High Country" is revealed candidly in Ang Lee's "Brokeback Mountain," an epic Western about forbidden love.

Anne Proulx's 1997 short story in the New Yorker has been masterfully expanded by screenwriters Larry McMurtry and Diana Ossana to provide director Lee with his best movie since "Sense and Sensibility" in 1995.

Featuring scenes filmed in the fabulous Canadian Rockies of Alberta and boasting a fine cast topped by Heath Ledger and Jake Gyllenhaal, "Brokeback Mountain" will appeal to moviegoers who enjoy grand filmmaking and poignant love stories, whether gay, hetero or otherwise.

The film, which screened in competition at the Venice International Film Festival, follows two men, Ennis Del Mar (Ledger) and Jack Twist (Gyllenhaal), and their love for each other that in the hide-bound and traditional world of the American West they must keep hidden, fearful not only of scandal but also for their lives.

Ennis and Jack meet in 1963 when they each show up looking for a summer's work herding sheep on Brokeback Mountain, Wyoming, on land owned by no-nonsense rancher Joe Aguirre (Randy Quaid). In order to keep his herd safe, Aguirre is happy to break regulations by requiring one of his men to roam high in the mountains, sleeping rough with no fire, while the other maintains a base camp with a one-man tent throughout the summer and into the fall.

There's nothing romantic about herding huge numbers of four-legged beasts left to range far and wide, and cowboys pretty much have cornered whatever romance there is in rugged outdoor animal husbandry. Riding herd on sheep guaranteed a horseman a hard time in old Westerns, but Ennis and Jack make the most of it, even if their diet is mostly beans.

They don't talk much, but Ennis speaks of being raised by his brother and sister after their parents died in a car crash, and of a woman named Alma he plans to marry. Jack tells of stern parents and working the Texas rodeo circuit. The scenery is breathtakingly gorgeous but their days are hard, with bears and coyotes threatening, and the biting mountain cold, and the two men soon come to rely on each other totally.

One night, Ennis decides to sleep by the fire rather than head off to his lonely post, but in the wee small hours, with the fire dead, he's freezing. Jack yells at him to join him in his tent. A simple human gesture in sleep prompts a frantic coupling that in the cold light of morning each man is quick to dismiss.

The summer ends, and as time goes by Ennis marries Alma (Michelle Williams) and Jack weds Lureen (Anne Hathaway), and they each have kids. The men's shared passion keeps its fire, however, and their affection and need for each other grows. Over the years, they contrive to spend time together back on Brokeback Mountain. Always there is the threat of exposure and the fear it breeds.

Pulitzer Prize-winner McMurtry ("Lonesome Dove") and Ossana, his writing partner since 1993 who has shepherded the project for eight years, use a large canvas for what is really an intimate story. They develop the secondary characters with great insight and compassion. The women in the lives of Ennis and Jack are given full attention, and the acting, especially by Williams, Hathaway and Kate Mara, as Ennis' daughter Alma at age 19, is deeply affecting.

The fine details of the West are as precise as you would expect from a McMurtry piece, and Lee's adroitness with the excellent cast is on full display, particularly in the brave and moving performances of Ledger and Gyllenhaal.

The dusty towns of Wyoming and Texas are contrasted with the spectacular Canadian Rockies, splendidly filmed by Rodrigo Prieto, and the film benefits enormously from composer Gustavo Santaolalla's melodic and plangent score.