BASED on a best-selling novel of the same name, Before I Go To Sleep is a grim psychological thriller revolving around the theme of memory loss.
After an accident in which she sustained head injuries, Christine (Nicole Kidman) suffers amnesia, thereafter keeping complete memories only up until her mid-20s – a decade of her life is a total blank.
Waking up feeling 20 – but then rapidly coming to terms with being 40 – is a horrific fate that we can all empathise with, but things are worse for Christine.
She awakes anew each morning to a house, a husband, and a life that is completely strange – no longer a university student, she is now living in the relatively affluent outskirts of London, with her loving husband Ben (Colin Firth), who is the head of the chemistry department at the local school.
Ben has a well-established routine that he wearily delivers over breakfast, which details their meeting, their marriage, and her accident.
Once Christine is in a suitable state of confusion, Ben leaves her in the house alone and goes to work.
However, a phone call from a Dr Nash (Mark Strong) each morning prompts Christine to find a camera she has hidden in the wardrobe, and reminds her that it must remain hidden from Ben.
Furtive self-shot video diaries are recorded on the camera from previous days, and they repeat the message that there are secrets being kept from her, and that she should trust nobody.
So begins another day of mystery as Christine attempts to build on the snatches of digital memory from yesterday to unravel the truth of the situation before sleep wipes everything clear.
Ostensibly, Before I Go to Sleep offers an interesting set-up for a thriller, with a dependent protagonist stuck in a bind between two unfamiliar, controlling men who each feed her contrary information.
By the nature of her accident, Christine becomes the ultimate unreliable narrator, and as viewers we remain in the dark alongside her when it comes to the aims of both Ben and Dr Nash.
Each day that passes is another turn of the screw that tightens dramatic tension, calling into question the sanity of Christine and motives of the other characters around her.
Before I Go To Sleep plays out like a nightmarish version of Groundhog Day, smearing over the snowy white charms of Punxsutawney with ashen London dreariness.
To his credit, director Rowan Jeffe manages to nail the right kind of atmosphere, teasing out the tension while maintaining a subtle air of menace that lies beneath the most mundane of circumstance.
Firth follows suit with his performance, skilfully walking the tightrope of ambiguity – we are never quite sure whether his efforts to guide Christine fulfil his best intentions or hers, or whether his outbursts of anger are the natural consequence of attempting to cope with the predicament, or if they betray some darker intentions.
As the pivotal piece of the puzzle, Kidman perhaps has too much placed on her shoulders, seemingly never stepping off camera for the entire duration.
While her scenes with Firth play out brilliantly, capturing both the tension and tenderness of the situation, there is some jarring overkill in the use of video-diary shots that have a tendency to rapidly cool down what is otherwise a happily bubbling broth of mystery.
It is something that could be overlooked if the rest of the film held up, but an unfortunate third act sees the tension and characteristic style descend into the safety of tried and tested genre conventions, resulting in a promising but fittingly forgettable film.