Zed, played by Jack Black, resides in a primitive village, sharing his life with Marlack, the village's top hunter, and a girl named Maaya, who unfortunately has her heart set on Marlack. Meanwhile, Oh, portrayed by Michael Cera, is a timid gatherer who has feelings for Eema, another gatherer who, like Maaya, is attracted to the strong hunters. Frustrated by the lack of respect from his fellow villagers, Zed succumbs to temptation and bites from the fruit of a forbidden tree, which leads to his banishment. He is soon joined by Oh, who also finds himself outcast.
As the duo wanders, they stumble upon the infamous characters Cain and Abel on a fateful day when a severe conflict leads Cain to slay Abel. Cain's sister, Lileth, a strong-willed woman, has little interest in Zed, despite her father's blessing. Cain's other sibling, Seth, is revealed to be gay, adding an unexpected twist to their complicated family dynamics.
After Cain’s heinous act is uncovered by their father, he escapes with Zed and Oh to a coastal town. There, they witness their tribe enslaved and attempt to buy back Maaya and Eema but are betrayed by Cain, who sells them into slavery instead. Just as they're being transported for auction, chaos erupts when soldiers from Sodom attack the caravan, allowing Zed and Oh to flee into the desert.
In a serendipitous encounter, the duo meets Abraham, who is preparing to sacrifice his son Isaac. Abraham warns them about the sinful city of Sodom, predicting its divine destruction. He attempts to circumcise them, leading to a hurried escape to Sodom, where they are captured and face a terrifying fate at the hands of the guards. In a twist of fate, Cain resurfaces, now disguised as a guard, rescuing them and incorporating them into the Sodom army.
Zed quickly becomes enamored with Princess Inanna, and she reciprocates his interest. The high priest, in a bizarre ritual, sacrifices a virgin to invoke rain, cementing the city's descent into depravity. Inanna takes a liking to Zed, believing him destined for greatness. However, she also leads him into the forbidden Holy of Holies, where the high priest discovers them—and Oh is hiding, setting off a chain of dire events.
Facing trial by a corrupt King and Priest, Zed makes a bold statement about being chosen by the gods, leading to an infamous sentence of starvation or exhaustion for him and Oh. The King decides to sacrifice Maaya, Eema, and even Inanna—whom he disdains—for their insolence. Provoked by the impending sacrifice, Zed rises up against their captors. The spectators interpret this as a sign of rebellion from a prophesied savior, joining him in his fight.
In the chaos, Zed defeats the King and the high priest, freeing Maaya in the process. Oh experiences a life-changing moment with Eema, ensuring her status no longer fits the criteria for sacrifice. With Inanna ascending the throne as queen, Oh and Eema make their way back to their village, while Zed and Maaya embark on a new journey to Egypt, marking the beginning of a new adventure filled with hope and resilience.
