The Brigadier's wife is dead. A terrible accident. Grieving, he searches for death, and finds his way to Avalon, the other-dimensional kingdom of the Catuvelauni.
The Doctor is also in Avalon, marooned. He's lost his companions, his TARDIS... and his hopes for the future.
Now it seems they'll have to make a new life for themselves with the Celts who live in the Dreamlands. Perhaps even help in the Celts' negotiations with the Unseelie, the sinister original inhabitants of Avalon, who live far to the North.
But then a gateway opens between Earth and Avalon. The British Army arrives in force. And the Brigadier negotiates a treaty that will lead to war in the Land of Dreams.
With fearsome dragons duelling jet fighters, vicious Gallifreyan agents causing havoc, and Compassion fighting against her ultimate fate, can the Doctor save the world, his best friend, and himself?