The threat of a war announced and never exploded against the mysterious Dark King hangs over the kingdom of Heptagonia, of which the young Aheànder has inherited the government following the untimely death of his father. The stalemate is suddenly interrupted when one night, during a fight with an onyx dragon, his wife Lizabeth disappears from the royal palace. Forced to face fears that have never been overcome and to measure himself against increasingly lethal opponents, the prince launches himself into a journey beyond the boundaries of the known world in search of sacred steel, the only weapon capable of opposing the enemy's advance. But that of Aheànder and his companions is also a struggle against time, because the lives of Lizabeth and the child she is carrying are hanging by a thread, and from the princess' past emerges a secret on which the very destiny of humanity depends.