It's almost Christmas and Maya is happily snapping pictures of the Christmas lights on Regent Street from the top of a bus. Everything seems perfect until she sees the couple arguing and, when the flash goes off, it reveals something unbelievable – the man has a gun in his hands. To make matters worse, the flash makes him look up. Suddenly Maya's a witness and, when a body turns up, she's whisked away from her immediate family to somewhere the police think is safe – her aunt's remote farm in the Welsh mountains. Cut off by the snow, Maya should have nothing to fear. But the police can be wrong.