In Mesopotamian mythology, the hero Gilgamesh embarks on an epic journey primarily centered around the quest for immortality. Accompanied by his friend Enkidu, Gilgamesh faces various trials, including battling divine creatures and seeking knowledge from the immortal Utnapishtim. This adventure underscores themes of friendship, loss, and the human condition, ultimately leading to the realization that immortality lies not in everlasting life but in the legacy and memories one leaves behind.