This audiobook is narrated by a digital voice.Jack Fynn’s dad isn’t dead. He’s just... missing. At least, that’s what the Army says. But when a funeral goes sideways and a mysterious stranger on a motorcycle roars into their lives, Jack and his twin sister, Macy, are pulled into something way bigger than they expected.That stranger? Their grandfather, Ace—a washed-up, semi-pro wrestler with a wild past and one colossal secret: he’s a Sentinel—protector of a hidden gateway t...