April is one of five foster kids living at Winterborne Home, a sprawling mansion full of secrets. The biggest secret is that Gabriel Winterborne, their reclusive millionaire guardian, is actually The Sentinel, a masked vigilante tasked with protecting the city. When Gabriel goes missing (again!) it’s up to the kids to find him before his enemies do. And when April’s past catches up with her, she will have to decide how hard she’s willing to fight to hold on to her new-found family when everyone seems determined to tear them apart.