using one story to explain another

Nathalie suggested I cross-post this here:

Benjamin asked me to read to him from my book. I told him I didn't think he'd like it. He asked me to please try anyway.

Rage:
Sing, Goddess, Achilles' rage,
Black and murderous, that cost the Greeks
Incalculable pain, pitched countless souls
Of heroes into Hades' dark,
And left their bodies to rot as feasts
For dogs and birds, as Zeus' will was done.
Begin with the clash between Agamemnon —
The Greek warlord — and godlike Achilles.

Which of the immortals set these two
At each other's throats?
Apollo,
Zeus' son and Leto's, offended
By the warlord. Agamemnon had dishonored
Chryses, Apollo's priest, so the god
Struck the Greek camp with plague,
And the soldiers were dying of it.
Chryses
Had come to the Greek beachhead camp
Hauling a fortune for his daughter's ransom.
Displaying Apollo's sacral ribbons
On a golden staff, he made a formal plea
To the entire Greek army, but especially
The commanders, Atreus' two sons:

"Sons of Atreus and Greek heroes all:
May the gods on Olympus grant you plunder
Of Priam's city and a safe return home.
But give me my daughter back and accept
This ransom out of respect for Zeus' son,
Lord Apollo, who deals death from afar."

A murmur rippled through the ranks:
"Respect the priest and take the ransom."
But Agamemnon was not pleased
And dismissed Chryses with a rough speech:

"Don't let me ever catch you, old man, by these ships again,
Skulking around now or sneaking back later.
The god's staff and ribbons won't save you next time.
The girl is mine, and she'll be an old woman in Argos
Before I let her go, working the loom in my house
And coming to my bed, far from her homeland.
Now clear out of here before you make me angry!"

The old man was afraid and did as he was told.
He walked in silence along the whispering surf line,
And when he had gone some distance the priest
Prayed to Lord Apollo, son of silken-haired Leto:

"Hear me, Silverbow, Protector of Chryses,
Lord of Holy Cilla, Master of Tenedos,
And Sminthian God of Plague!
If ever I've built a temple that pleased you
Or burnt fat thighbones of bulls and goats —
Grant me this prayer:
Let the Danaans pay for my tears with your arrows!"

Benjamin: Is the old man going where he's not supposed to?

Me: No, he's not going near Agamemnon's ships. He's going away from the ships. But he's about to do something that will get his daughter back.

Benjamin: Why the man took his daughter?

Me: Um. Well. You see, in ancient times, when grownups would fight, they would fight much worse than kids fight. And sometimes they would take people prisoner, and take them home with them as slaves — to make them work for them in their homes. Do you understand?

Benjamin: No, papa.

Me: OK, well it's very much like in The Wonderful Wizard of Oz, where the Wicked Witch of the West destroys (or seems to destroy) the Tin Woodman and the Scarecrow, but takes Dorothy and the Cowardly Lion back to her castle, and makes Dorothy clean the castle kitchen for her.

Benjamin: So does the old man throw a bucket of water on him?

Me: Yes. Sort of. Only instead of water, he hits Agamemnon with plague…