Imagine what it would be like to have "atypical psychogenic amnesia", like Nicole Kidman's English suburban housewife character Christine in Rowan Joffé's film, and to be unable to form new memories that last any longer than a day.
To wake up every morning in an unfamiliar world and an unexpectedly old body, and to have to take the word of the stranger beside you when he tells you that he is your husband of 14 years.
Unfortunately, what you have just imagined is probably more interesting and more plausible than this adaptation of SJ Watson's 2011 bestseller, which hardly seems to have thought about the consequences of Christine's condition at all.
A lack of consequence and an absence of character development are to be expected in a film about a woman whose life is reset every night, but these are challenges that Steven Knight's screenplay sets itself and then never rises to meet.
Christine's amnesia is just a plot gimmick.
Which would be fine if the plot was well organised or involving, but instead it boils down to the overly simple question of which of the two weirdly sinister men in her life she can trust: husband Ben (Colin Firth) or neuropsychologist Dr Nash (Mark Strong).
And the film's misdirections are clumsy and telegraphed, such that Christine isn't so much living in an unfamiliar world as an illogical one.
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