The most baffling film since - what? Donnie Darko? Mulholland Drive? That is liable to be one's initial reaction. But all is clear when one realises that everything between Chloe dozing off in the museum and waking in the ambulance is a dream. Louis does not exist, Sanda does not exist, the gun does not exist. Milo the cat is a clue. In the dream he is missing, then (in a dream within the dream, and an obvious wish fulfilment ) found, then missing again. Yet he is there at the end, He was never actually missing at all.