For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Bros Will Be Bros
Gilgamesh is immature; Enkidu is ignorant. Enkidu is initiated into the ways of humanity and heads to Uruk to confront Gilgamesh. After Gilgamesh and Enkidu fight, they become the closest of friends. Enkidu and Gilgamesh head off to the Cedar Forest in search of fame. Dun-dun-dun.
Act II
Faster Gilgamesh Kill Kill Kill
There, they kill Humbaba. Back in Uruk, Gilgamesh rejects the advances of Ishtar, and the two friends must do battle with the Bull of Heaven. They kill it too. Then, Enkidu dies.
Act III
Don't Drink the Water
Gilgamesh is consumed with grief for his friend. He journeys to the land of Utanapishtim, the survivor of the Flood. Utanapishtim tells Gilgamesh that humans can't live forever. He gives Gilgamesh a magical plant that will restore his youth, but Gilgamesh loses it on the way back home to Uruk. Oops.