If you are going to live a lie, there is no point in being half-hearted about it. To the chagrin of his beautiful wife Isabel (Alicia Vikander), Tom the lighthouse keeper (Michael Fassbender) just can’t stop himself from doing what he thinks is the right thing in this sometimes touching but mostly mawkish and terribly slow handwringer. Set in Western Australia (full marks to the location scout), Tom, returned from the annihilation of WWI, accepts the job of maintaining the lighthouse on the windswept island of Janus – the constant wind and grey skies provide no respite from the movie’s glum tone. He marries Isabel and they set up house with the chooks and goats and candles, making occasional visits to the mainland on salty Jack Thompson’s ferry. Grief descends on the lovers when Isabel has two miscarriages – the second is a truly agonising scene. But lo and behold, almost immediately after that tragedy, a rowboat with a swaddled baby girl and her dead father is washed ashore. (How DID he die? It’s never explained.) If that is not enough of a coincidence to make you guffaw, you will easily accept the proposition that the childless couple then decide to raise the kid, whom they name Lucy, as their own. After an exhausting first act, the nut of the problem, what the story is all about, is confronted when the real mother, Hannah (Rachel Weisz), makes a belated appearance. That Isabel’s parents or Thompson have never mentioned her loss stretches credibility. After Tom sees Hannah mourning at her dead baby’s headstone in the churchyard where he and Isabel have taken Lucy to be christened – it is pure Thomas Hardy – he is overwhelmed by the moral dilemma. Can the secret be kept? Will a wise Solomon emerge to ease the crises of conscience? Vikander does enough emoting for a handful of roles and Fassbender tends to overdo the steadfast but troubled quiet man, but Florence Clery as the little girl is delightful.