Oracle, Vol. 5: The Widow

Zeus cannot resist the charms of mortal women and his wife, Hera, is very jealous. In the Kingdom of Argos, a young woman confides to Cydippe that she is the mistress of the King of Gods. Zeus learns about this and orders Poseidon to drown the city along with his secret. Cydippe's husband and their children are among the many victims. Mad with sorrow, Cydippe calls upon Zeus and gives him an ultimatum: either he helps her to bring her family back from Hell or she will tell Hera everything...
Reluctantly, he gives her three magical artefacts: a cape of invisibility, a piece of chalk to go through walls, and a bronze sword in the shape of a thunderbolt that can invoke lightening. But each time she uses one of them, she will be indebted to him. Cydippe doesn't care, only one thing matters: to save her family from Hell.