At the end of his life, the Twelfth Doctor faced his darkest hour: losing beloved companions Bill and Nardole in an impossible stand-off against the Cybermen, and losing Missy to herself, not long after.Mortally wounded in battle, he could see no reason to go on.He was willing to die a final death.But a surprise, time-twisting encounter with his oldest self, the first Doctor, led him to recover his desire to go on - to start again.It's time for change. For regeneration.And the Doctor has a few things to say to the Doctor that is to come.For in his warren of memories and the many lives past lies the key to a brilliant future...