This is a really good parallel universes story. It wasn't overly technical, and it wasn't "cheesy" - just all around entertaining.
The main character, Maya, is a "Harlequin" - which means she is a warrior whose mission is to protect "Travelers" - those who can cross over into the alternate universes. The "Brethren" are the bad guys, and they co-opt one of two Traveler brothers.
There's plenty of action. The book is the first of a series. Highly recommended.
