The TARDIS materialises on board a still and eerie spaceship. When a squad of soldiers land, they realise they've found themselves in the middle of a war zone. With one of their crew trapped by the enemy, the Doctor and his friends find themselves locked in a desperate race for survival. Vast warships manoeuvre around each other as both sides try to out-think their opponents, flying into ever more dangerous areas of space.
The stakes could not be higher. But as ever in war, the lines between good and evil are hard to define. Will anyone survive to claim the moral high ground?