The magical final chapter of the Twelfth Doctor's (Peter Capaldi) journey sees the Time Lord team up with his former self, the first ever Doctor (David Bradley)'and a returning Bill Potts (Pearl Mackie), for one last adventure. The two Doctors find each other in an Arctic snowscape, refusing to face regeneration. Enchanted glass-like entities, who steal their victims from frozen time, and a World War I captain destined to die on the battlefield, but taken from the trenches to play his part in the Doctor's story. A tale about the power of hope in humanity's darkest hours, Twice Upon A Time marks the end of an era. But as the Doctor must face his past to decide his future, his journey is only just beginning.