The hero’s journey motif dominates the latter half of "Gilgamesh". Often seen as a timeless motif across cultures, the hero’s journey typically follows a lone protagonist as they arrive at transformation after a long, solitary journey and a series of decisive confrontations in which the hero is victorious. However, in the case of Gilgamesh, the motif is complicated by irresolution. After Enkidu’s death, Gilgamesh journeys in search of immortality, but after a series of victories and failures, he returns home empty-handed.

As is typical with the hero’s journey, Gilgamesh defies the odds by accomplishing various heroic feats. He passes through the underground tunnel before the return of the sun in Book 9, followed by a death-defying journey across the Waters of Death in Book 10. However, his quest is destined for defeat, and immortality remains out of reach despite his best efforts. In the end, Gilgamesh accomplishes superhuman feats but is defeated by his mortal body’s need to bathe and to sleep. He cannot stay awake for seven days to earn his immortality, and he loses the valuable plant of immortality when his back is turned, and his guard is down. The needs of the human body ultimately undermine his goal.