Ean (KIM Tae-ri) has a critical mission to return to the future to save everyone. However, she becomes trapped in the distant past while trying to prevent the escape of alien prisoners who are locked up in the bodies of humans. Meanwhile, Muruk (RYU Jun-yeol), who helps Ean escape various predicaments, is unnerved when he begins sensing the presence of a strange being in his body. Traveling through the centuries, they are trying to prevent the end of the world...