This trilogy is SO GOOD. You meet Tremaine as a young woman in a world that resembles WWII in the Blitz. She's from a wealthy family, she had been driving an ambulance for the aid service, and she's thinking that there's not much point left in life, when she's dragged into helping with a military project. It's a magical project -- both the invaders and her country use magic as part of their arsenal -- and she finds herself traveling into a very different society and adventure.

She's not what you expect a young woman from a wealthy family to be like, and you gradually learn that her father was not all that he should be, and he trained her up to be able to take care of herself, and her brains and ability to use a gun come in handy. But it's the tight-knit team that battles incredible odds that wins my heart. There's a down-to-earth, get it done quality in Tremaine that kind of reminds me of Cordelia from the Vorkosigan books?