Lena is an intelligent and strong Korean girl, serving as the captain of the Kendo team. She lives with her single mother, who proudly calls herself a 'Herb Fanatic.' When a new student, Hye-Min, transfers into her school and joins the Kendo team, he initially mistakes her for a boy. However, they soon discover their love for each other. Tragically, it is revealed that Hye-Min and Lena are half-siblings. Shocked by this revelation, Lena breaks up with Hye-Min. In response, Hye-Min's mother sends thugs after Lena. To protect Lena, Hye-Min is severely injured and nearly dies. Enraged, Hye-Min's mother then sends assassins who kill Lena's mother before Lena can warn her. Attempting to escape, Lena is stabbed by the assassins and falls into a nearby river. When she wakes up, she finds herself in a strange world where she might be its only hope.
Upon arriving in medieval Scotland, Lena hides her gender and calls herself "Ley," quickly gaining a reputation as a fearsome warrior. Her actions and words exude the charisma of "a born leader," causing many to follow her instinctively. Meeting Maren from the Leon tribe, who has the gift of speaking only the truth, Lena learns that she was originally from the current world. She was the child of Jira (Zira), who became a concubine of the King of Aran but was stolen as a baby by the previous Queen Arianna, who had become mentally unstable after losing her son to her daughter, who later became Queen Elinor. It remains unclear which world Lena truly belongs to. She is now the leader of "The Five."
