Na Bi is a former member of an idol girl group and now an actress, but her acting is poor. Meanwhile, Hong is a movie director who studied in Poland. He is recognized as a rising star in the movie industry. He became famous for sex scenes in his films.

A teenage girl is captured by a giant mutated squid-like creature that appears from Seoul's Han River after toxic waste was dumped in it, prompting her family into a frantic search for her.