Zeus and the skeleton army

Zeus and Hercules have gotten the Hydra's scale and the Amazon warrior queen's golden belt, and that leaves just one more task to complete to stop King Eurystheus from declaring war on Olympus--bring Cerberus, the three-headed hound of Hades, to King Eurystheus. Hoping Athena can help them convince Hades to let them borrow his hound, Zeus, Hercules, and Athena arrive in the Underworld only to be confronted by the mysterious Melinoe and her shadow army of skeleton ghost Nightmares.