Eunha, a fencing prodigy, finds herself as Selena Evan, a side character in a novel and daughter of a renowned swordsman. Her life takes a sharp turn when she gets transported into a fictional world, facing a grim fate at the hands of the villainous Prince Ignus. To save her family from execution after her twin brother flees military duty, she masquerades as him. However, her secret is in jeopardy as Ignus recognizes her exceptional swordsmanship, aiming to recruit her as his top henchman. Will Selena manage to evade capture and the threat of imminent death by outwitting the cunning prince?