在前往特拉奇斯的朋友刻宇克斯家途中，赫拉克勒斯遭遇了他一生中的最大危险。抵达奥宇埃诺斯河时，他目睹了涅索斯这个半人半马怪物，每次都向往来的人索取过河费。涅索斯自认为这是对得起良心的，因为神明相信他诚实，因此被赋予了这一义务。然而，当赫拉克勒斯的妻子得伊阿尼拉需要涅索斯帮助渡河时，情况变得复杂。

得伊阿尼拉年轻漂亮，迷住了涅索斯，他竟然用手在她身上乱摸起来。当赫拉克勒斯特ully heard his wife's cries for help, he saw the monster harassing her and was filled with fury. He quickly grabbed an arrow from his quiver and shot it at Neesoos as he stepped onto the shore, striking him down.

Despite being mortally wounded, Neesoos still sought revenge by telling Deianeira that she was the last person to hold him while crossing the river and therefore had a responsibility to bury him properly. He also deceived her into believing that if she used a vial of his final drop of blood to treat her husband's clothes, no other woman would ever win his love again. After saying these treacherous words, Neesoos died.

Deianeira took one cupful of Neesoos' final drop of blood without knowing its true nature or purpose. She and Hercules then experienced more adventures before finally finding their friend Guneus in Taphians land. Guneus welcomed them warmly and allowed them to stay with him on their journey.