This paper compares narrative modiﬁcation in the Mongolian heroic epic The Epic of Geser with that of the Buddhist Mulian story. The Mulian story, in which the protagonist saves his mother from the underworld gained widespread popularity in its time. Mulian Bianwen from the Tang dynasty, presents the scenes from the story in a very dramatic manner. The Mongolian Geser epic uses this motif but adapts the story to ﬁt the characteristics of a heroic epic for nomadic people. Heroic epics must contain motifs that depict the image of their protagonist to present a collection of exemplary characters. To create a complete heroic epic, the story of Geser absorbed a religious story from another culture that was very popular at the time. In the present study, ﬁve scenes common to The Epic of Geser and the Mulian story are analysed to investigate how the original Buddhist story became a part of the heroic epic. This analysis considers the ways in which identical story motifs can be used for the different purposes according to the nature of the literary work.