The Last Quest Of Gilgamesh by Ludmila Zeman

After the death of his close companion Enkidu, a powerful but troubled king embarks on a perilous journey to discover the secret of immortality, confronting monsters, strange lands, and wise figures along the way. He reaches the immortal survivor Utnapishtim, learns that eternal life carries costs, briefly finds a plant that can restore youth only to lose it to a serpent, and returns home transformed—accepting human mortality and taking up his role as a wiser, more compassionate ruler.

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