There are rules every mouse must follow, if they’re to survive in a forest that’s so much bigger than they are. With one younger sibling, another on the way, and a best friend with a penchant for trouble-making, Tobin knows the guidelines by heart. After all, he needs to be prepared for anything. But nothing could prepare Tobin for one stormy night when two monstrous arachnids steal his baby brother away.  The rules are clear: never chase a predator. But to rescue his brother, Tobin will do anything—even break a few rules. And out in the wild, miles beyond his safe burrow, Tobin must learn how to navigate the treacherous deep wood, befriend creatures bigger than he’s ever seen before, and create a new rulebook all his own.