First of all, the beginning:
At the beginning of the book is a basic summary of what happened in the previous book, Zeus - King of the Gods, in which the Titan-son of Earth and Sky, Kronos, swallowed all his children but one, who rose against him, made him vomit the children up, and then locked him and the other evil Titans in Tartaros. These children rose up as the 1st of the Olympians, the 12 major gods. Here in Athena, the Moirai (Moirai), goddesses of fate, tell the story of Zeus, king of the Olympians, who tricks his wife Metis into a game of shapeshifting after a terrible prophecy from Earth. Personally, I loved this part. Why I love watching a girl turn herself into various flying creatures including a dragon-like snake and then getting swallowed whole by her shapeshifting husband, I know not.