The Time War.
Dealing with the repercussions of degeneration, the Doctor has a limited window of time to evade capture, recruit old allies, wage a war, and find out what’s really going on. A warrior is being hunted by a mysterious stranger in a TARDIS. A rogue agent has been assigned a mission to eliminate a dangerous foe. This is a fight between a war criminal and a fugitive. A fight between Doctors.