UnBounded [Book 4]

Two months after escaping Tartarus and saving the world, Luke, Silena, Bryn, and Derek are trying to live as normal lives as possible for a demigod. But each one came out changed, some more than others, and it's affecting not just themselves, but their relationships as well. When Luke and Derek start acting strange, Bryn and Silena start trying to figure out what's going on and if it has something to do with the strange feelings they've been getting. However, no amount of training at camp or experience in Tartarus could've prepared the demigods for what they are going to have to do, and some of them wonder if they'll even come out of this alive, for they'd rather die than kill their best friend.