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, it's up to the kids to find him before his enemies do.

Full of adventure, gadgets and humour, the second book in the captivating new series from the bestselling author of Gallagher Girls will have you hooked!