With the help of the valkyrie Reginleif, who sent the Norsemen to Egypt, the heroes locate Gargarensis and the Tartarus gate. Inside the Norse underworld Niflheim, they are pursued by fire giants until Chiron sacrifices himself to hold them off, saving his friends. While Gargarensis is trying to knock down the gate, Brokk and Eitri have been rebuilding Thor's hammer (shattered by Loki), that upon completion seals the gate. Back on the surface, they confront Gargarensis with the help of Odysseus, who has made a detour to help them, and the cyclops is captured and beheaded.