The third book in the New York Times-bestselling Tunnels series! Deeper ended with Will and Chester head over heels in Freefall — tumbling through the subterranean Pore with the evil Rebecca twins in hot pursuit, both toting phials of the lethal Dominion virus. When, where, will they ever land?! Just when the drop seems infinite, the boys find themselves in a realm of near-zero gravity, on a spongy fungus concealing artifacts from some prehistoric Eden at the center of the earth. But they are not alone. They may be on the edge of an underground heaven, but with the Styx dead-set on enslaving Topsoilers, all heck's breaking loose up above.