At night, armies of men are fighting. With the battle over, the victors run off leaving the bodies lying on the ground. As the corpses lie there, something comes and drags them away. Elsewhere one of the deceased soldiers, Aelon, appears at his home, as a ghost. He tells his brother, Krytus to help him. Krytus goes to find Hercules and Iolaus and asks them for their help. When he explains that someone is stealing the bodies of the dead soldiers, Hercules and Iolaus agree to return to Tantalus with Krytus. He tells them there has been trouble there since King Memnos died three months earlier.
Hercules and Iolaus arrive at the castle and Daulin, Memnos' son, greets them. He plans to lead an attack against Poena, his sister, who is trying to overthrow him. He tells Hercules that Poena's men are stealing the bodies of the dead. Hercules goes to talk with Poena; she tells him that Daulin killed the king using poison. She accuses Daulin of stealing her dead soldiers; Hercules is suspicious that both armies' dead soldiers are being stolen; he heads off to investigate.
Hercules arrives at the battlefield and finds some armor and a paw print, concluding it belongs to Graegus, Ares' dog of war. Daulin calls for Iolaus to explain why Hercules has gone to see Poena. Iolaus says Hercules just went to talk and that he would never betray a friend. Daulin accepts this but still plans an attack on Poena's camp that night.
Two mercenaries come to Poena's camp to join her side, when they see the general of the army, Jarton; one recognizes him and flees, dragging the other with him. Hercules returns to Poena, telling her that Graegus' presence means that Ares is also close by. He says Ares is using both sides to supply bodies to feed Graegus and begs Poena to stop the war. Later, the mercenaries are camping and one tells the other he killed Jarton months earlier. As they are talking a figures comes through the trees and kills them both, Hercules hears the screams and runs to help. The figures summons Graegus to drag off the bodies and Hercules arrives too late to see anything.
Iolaus slips away from Daulin's castle looking for Poena's camp. He runs into Jarton, who quickly disappears. He is captured by a group of soldiers and taken to the camp. Iolaus asks Jarton why he was doing by the woods; Jarton says he has been at the camp all the time. Iolaus takes Hercules to the place where he met Jarton and he meets Jarton's ghost. He tells Hercules that he was killed some time ago and Ares is using his body to continue the war. He informs Hercules that Ares killed King Memnos and with their bodies missing, they cannot be given proper ceremony their spirits are trapped in limbo between life and death.
At the camp, Poena tells Hercules that Iolaus went off with Jarton; he finds Iolaus tied to the roof of a cave. Ares mocks him and calls Graegus to kill the two men. Jarton returns to camp and tells Poena that Hercules was a spy for Daulin and they need to attack immediately. Hercules and Iolaus fight Graegus in the cave and succeed in tying him up; they run to the river where the two armies have met. The two men run into the river between the two armies, urging them to stop. The armies continue to advance until the ghost of the slain soldiers appear in the river with Hercules and Iolaus. Jarton's ghost tells them that Ares killed Memnos, not Daulin. Ares then begins fighting Hercules, blasting him with successive lightning bolts. Hercules refuses to fight back, as the soldiers throw down all their weapons, Ares weakens and melts away into the river, and Graegus bursts into flames.
The same evening, Hercules, Iolaus and some others carry a coffin into the cave to be buried. The ghosts of the soldiers appear again; Jarton tells the mourners they can now pass over to the other side. With the soldiers now at peace, Hercules collapses the entrance of the cave so they will never be disturbed again.