Kia, Envoy and Whonkahonk meet up at the Olympian station for the Trans-Nordikan Railway, and go to a chamber that is the entrance to the underground "Moltpaa Express", finding evidence of still-functioning part-magical / part-mechanical "stoneworks" of the long-gone "Moltpaa empire". Underground, they see the bizarre spectacle of the "Underground Ocean" lying beneath the Lake of Languor, and take a ride on a "train" that rides underground tracks. Further on, during their journey, they have to "switch trains" – without stopping! – and manage to do so successfully, though Whonkahonk gives them precious little forewarning. The next peril they face is when the train heads into a flooded tunnel. Quick-thinking tinker Kia gets out some caulk and temporarily seals the cracks in the doors, as while the carriages may have once upon a time been sealed against moisture and noxious fumes, the carriage they are presently in is obviously no longer water-tight. This gambit succeeds, and they eventually reach their destination at the underground city of Stalto.