Tunnels

When fourteen-year-old Will Burrows and his best friend Chester stumble upon a hidden passage in their cellar, they are whisked away to the Colony — a vast, ancient civilization thriving beneath the Earth's surface. But the discovery comes with a deadly price: a shadowy organization called Styx is hunting anyone who knows the way down. After Will's father vanishes under mysterious circumstances, the two boys must flee the Colony's dangers and journey deeper into the unknown to find him, pursued by agents who want the secret of the underground world buried forever.