Winterborne Home for Mayhem and Mystery (Winterborne Home for Vengeance and Valour, 2) by Ally Carter: Two sword-wielding vigilantes.
Five orphans. One mansion. No rules. April thought she had her happy ending. After all, she has her new house and new friends and new guardian. But she also has a very big new secret. The kids of Winterborne House are the only ones who know that Gabriel Winterborne”famous billionaire and terrible cook”is really a sword-wielding vigilante. What they don't know is that he's not the only one.
When a masked figure breaks in, looking for something”or someone”it's clear that Gabriel has met his match, and now no one is safe. April and her friends will have to solve a decades-old mystery in order to hang on to the most important thing in the world: each other.