I'm actually not a big fan of alt-histories, especially not those dealing with World War II. Because World War II was depressing enough, and alternative histories usually manage to make it even more depressing. But how can you resist Nazi X-Men vs. British warlocks? Bitter Seeds is a SFF alt-history in which mad science meets mad sorcery, and by the end of the book, history is completely altered... and probably going to get worse before it gets better. Be aware that this is the first book in a trilogy, and a number of loose threads are left dangling.
Here is the summary from Goodreads:
It’s 1939. The Nazis have supermen, the British have demons, and one perfectly normal man gets caught in between
Raybould Marsh is a British secret agent in the early days of the Second World War, haunted by something strange he saw on a mission during the Spanish Civil War: a German woman with wires going into her head who looked at him as if she knew him.
When the Nazis start running missions with people who have unnatural abilities—a woman who can turn invisible, a man who can walk through walls, and the woman Marsh saw in Spain who can use her knowledge of the future to twist the present—Marsh is the man who has to face them. He rallies the secret warlocks of Britain to hold the impending invasion at bay. But magic always exacts a price. Eventually, the sacrifice necessary to defeat the enemy will be as terrible as outright loss would be.
Alan Furst meets Alan Moore in the opening of an epic of supernatural alternate history, the tale of a twentieth century like ours and also profoundly different.
So, the Nazis have a group of superhumans raised by a mad scientist. Each of them has a single super power, powered by batteries that attach to electrodes in their skulls. No battery, no powers, which makes for an interesting limitation on all of them, but other than that, their powers are on a par with comic book superheroes. There's a telekinetic who can throw tanks and a pyrokinetic who can melt bullets in midair and burn through forests, but the really interesting characters are much less flashy: the brother and sister Klaus and Gretel. Klaus is the German POV character. His power is the ability to turn insubstantial, making him a perfect infiltrator, saboteur, and assassin. He's loyal to the Reich, but he's less sociopathic than his peers, including his sister. His sister, however, is the character around whom the book really revolves, because Gretel is an oracle. She can see the future with pinpoint accuracy, and it's thanks to her that for the first part of the book, the Germans roll unstoppably across Europe and are poised to invade an almost defenseless Britain. It's pretty clear that she is playing her own game, even while supposedly guiding the Nazis to victory, and she makes for a really frightening antagonist. Even after the British find out what they're dealing with, how do you fight someone who knows exactly what you're going to do before you do it?
The main British POV is secret service agent Raybould Marsh, who is most interesting because he has no powers or special abilities at all. He's a great spy, but he has to contend with warlocks and supermen using only his wits and a firearm. For the most part, he manages to pull this off without seeming completely outmatched, though he does benefit from a bit of luck now and then.
The British warlocks don't actually do magic themselves. Instead, they summon extradimensional beings called Eidolons and ask them to perform services for them. Here is where the morality gets murky: Eidolons don't like humans. They demand blood sacrifices. For small favors or little bits of information, a few drops of blood -- or a fingertip -- will do. But if you want them to, oh, say, destroy a German invasion fleet, well, that's going to take a lot of blood... Seeing the gritty reality of the blood sacrifices that both the British and the Germans are making blurs the line between good guys and bad guys. (Though it must be said that the book itself barely touches on the evils of the Third Reich; we know the Nazis are the bad guys mostly because historically they were the bad guys, not because they act particularly worse than the British in this story.)
This is very much an action-and-adventure novel, one that almost seems designed to be made into a movie. That's not a bad thing; it's detailed, meticulously researched, the magic and the super powers are well-conceived, and it's a page-turner from start to finish. No boring lulls in the plot, no heavy-handed exposition or extraneous drama. However, this does mean that things pretty much happen in a constant stream of events, and so the characters are painted in fairly broad strokes. We learn about their personalities and motives entirely through their actions, and while they are all interesting, none of them are really compelling -- there's no one who will make me say, "Oh no he didn't!" if the author kills the character off in the next book. This is the antithesis of a character-driven novel; it's almost pure storytelling. I liked it, overall, and it's further helped by the fact that Tregellis is quite a good writer, with just the right amount of description and action, but I do wish there was just a little bit more characterization.
Verdict: A great book that should slow down now and then to let us care a little more about the characters, but A+ entertainment, and one of the few first-in-a-series novels I've read recently where I'm really looking forward to the next book.