A decade after his heroic defeat of the monstrous Kraken, demigod Perseus is living a quiet life as a fisherman with his young son, Helius. However, the peace is shattered when Zeus visits Perseus, revealing that the gods are losing their power as humanity has ceased praying to them. This weakening has allowed Kronos, the leader of the imprisoned Titans and father of Zeus, Poseidon, and Hades, to seek freedom from his prison in Tartarus. When Hades and Ares betray Zeus, capturing him and draining his divine power to revive Kronos, Perseus reluctantly comes out of retirement to rescue his father and save humanity.

With the assistance of Queen Andromeda, the demigod Agenor (Poseidon's son), and Hephaestus, Perseus embarks on a perilous journey into the Underworld. Along the way, they encounter formidable creatures and navigate treacherous landscapes while facing their internal struggles. As they approach the heart of Tartarus, the stakes are raised, and the fate of both gods and humans hangs in the balance. Their unity, courage, and determination are tested as they prepare for an epic confrontation with unimaginable forces.