Hellboy meets Raiders of the Lost Ark in the stunning conclusion to Ian Tregillis's Milkweed series.

12 May 1940. Westminster, London, England: the early days of World War II.

Again.

Raybould Marsh, one of Britain's best spies, has traveled to an alternate Earth in a desperate attempt to save at least one timeline from the ancient alien race who have been observing our species and who have already destroyed Marsh's timeline. In order to accomplish this, he must remove all traces of the supermen that were created by the Nazi war machine and who caused the specters from outer space to notice our planet in the first place.

His biggest challenge is the mad seer Gretel, one of the most powerful of the Nazi creations, who has sent a version of herself to this timeline to thwart Marsh. Why would she stand in his way? Because she has seen that she dies in all the timelines and she is determined to stop that from happening, even if it means destroying most of humanity in the process. And Marsh is the only man who can stop her.