Read manga: Wild School

manga
Summary:

You-Geon, a high school student, is saved from drowning by a mysterious girl his own age. Indeed, this girl is a North Korean agent trained to kill. The encounter which will completely change You-Geon's peaceful life means that this mysterious girl never leaves You-Geon alone for a second worried he might reveal her secret to someone. The atmosphere at the high school will never be the same again..