After being fired, Walter Mitty (Ben Stiller) travels all over the world in search of photographer Sean O'Donnell (Sean Penn), hoping to find the crucial missing photograph that O'Donnell wanted to appear on the cover of the final paper edition of Life Magazine. Walter finally finds O'Donnell in the mountains of Afghanistan, where he's trying to photograph a snow leopards. O'Donnell reveals that the photo was inside the wallet he'd sent to Walter, a wallet Walter had thrown in the trash.
A snow leopard appears, but O'Donnell doesn't bother to take its picture. He tells Walter that sometimes, it's more important to experience a beautiful moment than to take pictures.Minutes later, he joins an impromptu soccer game with some nearby Afghan villagers. Walter joins the game, too.
When Walter returns home, he learns that his mother (Shirley Maclaine) has saved the wallet and the missing photo. Walter takes the photo to Life Magazine's offices, and gives it to the magazine's new boss, Ted Hendricks (Adam Scott). He pointedly tells Ted that many, many people have worked hard over the years to make Life a successful magazine, and that Ted owed all those people far more respect than he'd given them.
After his travels, Walter is more adventurous and confident. He hooks up with Cheryl (Kristen Wiig), who seems receptive to his advances. They stop at a newsstand together and look at the final print edition of Life magazine: Sean O'Donnell had taken a picture of Walter Mitty himself, as a symbol of all the dedicated employees who had made the magazine great.
Thanks John L!