Atrahasis carries the earliest connected form of the Mesopotamian flood story. Enki, forbidden to warn humanity directly, speaks his warning to the reed wall of Atrahasis' house; Atrahasis builds a boat, seals it, loads his household and animals, and survives the deluge that destroys the rest of humankind, ending with a sacrifice to which the hungry gods gather. This account was taken up and adapted by the flood narrative of Gilgamesh Tablet XI (where the survivor is Utnapishtim), and it stands behind the shared Mesopotamian tradition to which the Genesis flood of Noah is the biblical parallel, the same core sequence of divine decision, warned survivor, boat, deliverance and sacrifice. Because Atrahasis is the oldest of the three, it anchors the flood cluster the atlas draws between them.
The reasons the gods give for wanting humanity destroyed shift across the epic in a way scholars read as pointed rather than incidental: plague, drought and famine are each sent because human "noise" disturbs Enlil's rest, a strikingly petty motive compared to the moral corruption driving the comparable Genesis flood, where humanity is destroyed for wickedness and violence rather than for being loud, a contrast often cited in comparative discussions of the two traditions' pictures of divine motivation. The final tablet's account of the gods, starving without human sacrifice during the flood and crowding "like flies" around Atrahasis's offering once he disembarks, is read as an unusually candid admission that the gods needed humanity's ritual service as much as humanity needed the gods.