Stranded on a parallel Earth, the Tenth Doctor finds himself mentoring a traumatized child soldier enlisted in a hopeless war to save humanity. With an endless number of mysteries in sight -- from the enigmatic alien invaders they call Angels, to the strange machines known as Evangelions used in the planet's defense, to the shadowy maneuvers of those in power -- the Doctor is drawn deeper and deeper into a web of mistakes and sins that threaten to consume all humankind. In time, he'll face the darkest question of them all: what if there are some worlds -- and some children -- even the Doctor can't save?

After Alex Cole, an average 17 year old boy, has his heart crushed by the best friend he's been in love with for the past year, he doesn't really know what to do with himself. But after coming across a stray cat he found on the road, Alex's world is turned upside down.