On the journey back to Solis, the Fantasia are diverted from their route because of landmines. They must now travel through Urukopaina - radioactive tunnels of the dead. Guided by the Tunnellers, hopelessly mutated humans who can tunnel like moles, they make their journey through the passageways. What they don't know, however, is that the landmines were planted by Ozul and Maska, who wished them to travel through Urukopaina - as such, the Fantasia face many dangers underground.