A synopsis of the synopsis based on the first five chapters because the actual description is NOTHING:
Baek Hee-su is suddenly transported into an unfamiliar, foreign world infested with zombie-like creatures called Mannock/Manoc. After witnessing a brutal mascara from the Mannock and then getting kidnapped and threatened by mercenaries speaking a language she can't understand. The first person she meets in such a desperate situation who didn't try to hurt or kill her is the mysterious Kalix Clovis, a wandering mercenary who hunts the Mannock.
Although hesitant, he ends up allowing her to accompany him until she can safely reach the city he has sworn away from. "I will never meet you again once we arrive in the city. Until then, stay by my side".
Baek-Hee-su, who desperately wants to make it back to her own world, follows him persistently as her last salvation.