Winterborne Home for Mayhem and Mystery (Winterborne Home for Vengeance and Valour, 2)

Five orphans. Two sword-wielding vigilantes. 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.