Alluded to from the New Kingdom; a long demotic version survives from the Roman period
The distant goddess
The Eye of Ra storms off to Nubia in a rage, and the world dries up until she can be talked into coming home.
The Eye of Ra, a goddess who is variously Tefnut, Hathor or Sekhmet depending on the version, quarrels with Ra and leaves Egypt for Nubia, where she lives as a wild lioness. Without her the land suffers.
Ra sends Thoth to bring her back. He cannot compel her, because she is more powerful than he is, so he argues, flatters and above all tells her stories, a run of animal fables embedded inside the myth. Gradually he talks her round.
She returns north along the Nile and is pacified on the way with water, music and dancing, and arrives in Egypt as the gentle goddess rather than the lioness. Her arrival is the inundation.
Where it comes from
The Myth of the Sun's Eye
A long demotic papyrus of the Roman period, containing the embedded animal fables, some of which have close parallels in the Greek Aesop tradition.
Temple reliefs at Philae, Dendera and Kom Ombo
Ptolemaic. The return is celebrated in festival scenes.
What the story was for
The inundation, and the temperament of a goddess who is dangerous and necessary in the same body. The pattern of a fierce goddess pacified by drink, music and dance runs through Egyptian religion, and it is the same pattern as the red beer in the Destruction of Mankind. It is also the clearest surviving case of a myth told for entertainment: the fables Thoth uses to persuade her are stories inside a story, and they are good ones.
Other myths