Perseus and Andromeda's wedding banquet does not go as planned. In the midst of the festivities, the king's brother, Phineus, starts making an uproar.
He claims that Perseus has stolen his rightful bride, Andromeda (who is also his niece). Even though King Cepheus tries to talk him down, Phineus throws a spear at Perseus, but misses him.
Then all hell breaks loose, as the banquet erupts into a battle. Perseus kills various men in the battle.
Eventually, Perseus ends up without a weapon, facing hordes of incoming enemies. He decides that it's time to bust out the big guns—and lifts up the head of Medusa.
Now, everyone who tries to attack him turns to stone. Perseus also accidentally turns to stone somebody on his own side, his friend Aconteus.
Finally, when almost all of his friends have been turned to stone, Phineus throws himself at the mercy of Perseus, begging for his life. He averts his eyes, so as not to look at Medusa.
In response, Perseus says, "Don't worry; I want to keep you around my palace forever." Then he puts the Medusa head in front of Phineus's eyes and turns him to stone.
Next Perseus continues to wander the world. In his travels, he uses the Medusa head to turn various annoying people to stone.
At a certain point, the goddess Minerva, who has up until now been with Perseus every step of the way, checks out to visit the Muses on Mt. Helicon. There, the Muses gather around a spring of water emerging from a hole in the earth earlier struck by Pegasus's hoof.
The Muses graciously receive the goddess Minerva.
Then, one of the Muses tells her about how the evil King Pyreneus once tried to hold all the Muses prisoner. In this instance, the Muses escaped by flying away. Crazy old Pyreneus suddenly got it into his head that he could fly, too. He tried to chase after them, fell from the height of his fortress, cracked his head open, and died.
When the Muse stops telling her story, Minerva hears voices up above. She looks up and sees nine magpies perched on a tree-branch, imitating the voices of those below them.
One of the Muses explains that these were nine mortal sisters known as the Pierides (i.e., the daughters of Pierus) who challenged the Muses to a singing contest.
She says that the Muses thought such a contest was beneath them—but they thought if they refused the challenge they'd end up looking bad all the same.
The Pierides were up first. They sang about the battle between the gods and the Giants. According to the Muse telling the story, the Pierides' song was full of factual errors.
At this point, the Muse asks Minerva if she wants to hear the song the Muses sang in response to the Pierides. Minerva says she would love to hear it. With this encouragement, the Muse continues her story.
She says that the nine Muses nominated one of their number—Calliope – to sing for all of them. Then, when Calliope stood forward, she announced that she wanted to sing about Ceres, the goddess of grain. (Known in Greek as Demeter; you can read about her here.) Here's what Calliope recounted in her song:
One day, as Pluto, god of the underworld, was riding over the earth (he had left his kingdom to make sure there were no cracks in the earth's surface), he was spotted by Venus, the goddess of love.
She turned to her son, Cupid, and instructed him to shoot an arrow into Pluto to make him fall in love with Proserpina, Ceres's daughter. In this way, Venus would be able to extend her power even to the underworld.
At the moment when Cupid's arrow struck, Pluto was riding in his chariot past a field where Proserpina was picking flowers. Suddenly overpowered by love, he scooped up Proserpina into his chariot and carried her off to the underworld.
Their route takes them through a lake presided over by Cyane, a Sicilian nymph. Cyane tries to convince Pluto not to carry Proserpina off by force, but he ignores her. In shock, Cyane cries until she turns entirely to water, becoming one with the lake.
Meanwhile, Ceres, who did not know what had happened to her daughter, was searching for her all over the face of the earth.
One day she came to an old woman's cottage. The woman offered her a drink made of water mixed with barley. When a young boy came up and made fun of her for chugging it down too fast, Ceres threw the drink in his face. He instantly turned into a spotted newt.
After this breather, Ceres continued her quest.
Once day, she came to the pool in Sicily where Pluto and Proserpina had entered the underworld. Cyane, the nymph, couldn't tell Ceres what had happened, since she had been turned into water. But she did send a message of a different sort, when Ceres caught sight of Proserpina's girdle, floating on the surface of the water.
Seeing this, Ceres realized that her daughter had been kidnapped. She fell into profound grief. Because she was the goddess of the harvest, plants began dying all over the world—but especially in Sicily, the site of her daughter's abduction.
When things got really bad, Arethusa, the presiding goddess of a spring in Sicily, begged Ceres to come to her senses.
Then Arethusa told Ceres that, while she was flowing underground, she had caught a glimpse of Proserpina in the underworld. Arethusa told Ceres that Proserpina was now Pluto's queen.
After she heard this news, Ceres was momentarily stunned; then she headed up to the heavens, where she asked Jupiter to rescue Proserpina (their daughter).
Jupiter thought about it, then said, "OK. She can come back—but only if she hasn't eaten anything while in the underworld."
As it turned out, she had eaten seven pomegranate seeds. Only one person had seen her do it – a guy named Ascalaphus, the son of one of the nymphs of the underworld. Because Ascalaphus ratted her out, Prosperina transformed him into a screech-owl.
Then, Calliope (who has been telling us this story, remember?) revealed that the other girls who had been playing with Proserpina ended up being turned into the Sirens.
But what about Proserpina, you're wondering? Well, here's what happened. Jupiter worked out a deal: Proserpina would stay underground with her husband Pluto for six months of the year; the other six months she would spend with her mother Ceres. This is why we have seasons: the half of the year when Proserpina is gone corresponds to Fall and Winter, when Ceres's grief prevents plants from growing.
Now that everything was OK with Ceres, she went back to Sicily to resume her conversation with Arethusa. She wanted to know why Arethusa left Greece and became a spring in Sicily. Here is what Arethusa tells her:
Arethusa used to be a nymph living in the woods of Achaea, in Greece. One day, she came to a river that was remarkably clear, and decided to go swimming in it. The god inhabiting this river, Alpheus, instantly fell in love with her, and called out to her.
When Arethusa ran away, naked, he chased after her.
They ran over vast distances, until Arethusa suddenly ran out of strength. As she collapsed, she prayed to the goddess Diana to protect her. Diana heard her prayer, and wrapped her in mist, making her invisible to Alpheus.
But Alpheus didn't go away. Instead, he inspected the low-hanging cloud that had suddenly appeared before him. In fear, Arethusa began to sweat, turning into a puddle. Then, Alpheus turned himself back into his river form, so he could mingle with the puddle. In this way, Arethusa and Alpheus were joined in love.
In this new form, they plunged underneath the earth, eventually reappearing aboveground in Sicily. That was the end of Arethusa's story. (Explains everything, doesn't it?)
Then, with a final anecdote about how Ceres saved an Athenian named Triptolemus from being killed by the king of Scythians, Calliope finished her song.
The nymphs, who were judging the contest between the Pierides and the Muses, declared the Muses the winners.
But the nymphs wouldn't accept it; instead, they started spouting insults against the victors.
In response, the Muses turned the Pierides into magpies.
Wow, that was complicated. Before we move on to the next chapter, let's just get a recap on where we stand with all these stories-inside-stories. Basically, it goes like this:
(1) Minerva goes to the Muses and asks them what's up.
(2) The Muses tell Minerva about a singing contest they won.
(3) The Muses tell Minerva that, in that singing contest, Calliope told a story about Ceres.
(4) The Muses tell Minerva that, in that singing contest, Calliope told a story about Ceres in which Ceres met Arethusa, who told her own story.
Bear in mind that, when Book 5 ends, we're still in level (2), because it ends with the Muse still telling Minerva what happened.