The void has always existed: "No place. The silent realm. The lost dimension." The endless, empty space between universes. But the void is no longer empty. A spark has been lit in the emptiness - a spark now grown into an entity powerful enough to shatter creation. The void is hungry. And it is already here. This is a threat bigger than us. It's more than one Doctor can handle - and even the Doctors alone may not be enough! This is the lost dimension!