One of the best ways to keep the cold out during the winter season is with a nice heartwarming film, and while there isn’t much in the way of holiday-themed movies coming out in December, Ben Stiller’s new comedy The Secret Life of Walter Mitty definitely looks like one of the more upbeat offerings.

A brief glance at the synopsis might give the impression that The Secret Life of Walter Mitty is too depressing for a Christmas movie. Stiller plays a timid office worker at Life magazine who was never really done anything exciting or been anywhere interesting in his life, and who is so afraid of taking risks that he has to work up the courage to even send a virtual wink to the woman he has a crush on (Kristen Wiig). All this changes, however, when he sets off on a global quest to find a missing picture that is desperately needed to complete the next issue of Life.

Based on the short story by James Thurber that was originally adapted for film in 1947, The Secret Life of Walter Mitty has already received mixed to positive reviews from critics and the trailers so far have been visually impressive and boasted some genuinely funny dialogue. The new extended international trailer is no exception, featuring a mix of clips from the previous trailers along with enough new material to be worth watching.

One aspect of this premise that could potentially be explored in a compelling way is whether or not Walter’s real life adventure matches up to the euphoria of “zoning out” and imagining a grand scenario – or if it outdoes it. His life might sound pretty dull, at least at the start of the film, but would he have developed such a vivid imagination had he not been compelled to as an escape from blandness?

Another thing that makes The Secret Life of Walter Mitty look so interesting is its use of an unreliable narrator, which means that even whilst watching the trailers there’s an uncertainty as to whether or not the journey he embarks on is really happening or is just something else that he’s imagining.

The only way to find out (aside from reading spoilers) is to check out this comedy when it arrives in theaters at the end of the year.

The Secret Life of Walter Mitty is scheduled for release on December 25th, 2013.