There are times when cinema excels by focusing on an extraordinary, seemingly forgotten story. Museum tells the true incident of a heist of the National Museum of Anthropology in Mexico City. Taking place over the Christmas period in 1985, it was an audacious crime performed by two unknowns, wrong footing authorities enough to send them searching for a gang of professional art thieves.

Telling the duo's story through the robbery and its frustrating aftermath, Museum benefits from the exceptional work by its lead actors. Leonardo Ortizgris is an endearing presence, carrying much of the emotional weight of the crime that takes place. But it is Gael García Bernal who stands out, giving the film a cinematic swagger. He has the charisma of a 70s movie star, whilst just about carrying the surprisingly heavy moments of the second half, where the film becomes weighed down with existential angst.

The great flaw of Museum is that the most interesting, exciting sequences reside in the film's first half. There is, however, a hidden treasure once the film leaves Mexico City in the performance of Simon Russell Beale. With his role kept to a single scene, Beale plays a barnstormer as the antiquity collector the duo try to sell their products to. He has a fascinating speech where he sets out for our heroes the consequences of their actions and how, in essence, what is priceless is in fact worthless. In an over long and somewhat rambling second half it is a moment that particularly stands out.

When the film reaches its climax the audience can't help but return to the heist that set off the film's narrative. While the motivation for this feels murky, with the film not offering its heroes the excuse of returning these items to their original home, it is executed exceptionally. The film wallows in the thieves' craft and the whole fifteen minute sequence is one of the finest cinematic heists of recent years. For all the frustrations in Museum's second half and the heaviness of its angst, it is in these moments that movie shines.

This is a London Film Festival preview and Museum will be released at a later date.