So "James" (Asa Butterfield) and girlfriend "Hayley" (Cora Kirk) are saying their goodbyes before heading to their respective families for Christmas. It's only when they are on their separate trains that they realise that they would rather be together, so - without telling each other - they board the other's train. Next thing, she arrives at his and he arrives at her's and what now ensues is a gently comedic tale that quite engagingly illustrates the joys and pains of the season. It turns out that neither have been being entirely honest with each other, or with their families - but can that all...