True to its title, this film is a virtual masterclass in storytelling, not to mention an extremely intimate and personal project for the up-and-coming young Canadian actor-turned-director Sarah Polley (Away from Her; Take This Waltz).

While the film takes the form of a documentary about her vivacious late mother, Diane, the end result is closer to Mike Leigh’s classic Secrets and Lies, than to the self-indulgent home movie you might reasonably fear from that description.

Diane and her husband, Michael, both Toronto actors, seem to have been a slightly odd couple. Apart from the tensions produced by their contrasting personalities (her perpetually switched-on livewire to his down-to-earth rock) this nonetheless initially appears to have been a relatively unremarkable pair of lives.

But there are secrets – and indeed lies – waiting to be uncovered. Polley proves expert at holding back key information, revealing it at a point where she can most effectively recreate her own emotional journey into what she belatedly realised were mysterious circumstances surrounding her childhood.

Constructed from an intelligently chosen blend of interviews with family members and friends, as well as home movie and faked home movie footage often fiendishly hard to tell apart, this exceptional film proves the adage...