December has the shortest days, the darkest nights... In the ruins of a medieval abbey on the Welsh Border, four young musicians start work on an album influenced by the site's bloody history. It's December 1980 - the night John Lennon will be murdered in New York. And there'll be more horror before the sun rises and the session tapes are burned. Or are they?
Years later, Moira, Dave, Tom and Simon are persuaded to return to the abbey to complete the recordings they thought had been destroyed. But the old tapes - and all the darkness they contain - have been restored. And it's December again.