Lena was just an average girl until she stumbles upon an Otherworlder, a dangerous entity who arrived from an alternate dimension called "Earth" through a mysterious spell known as "isekai". Though it may look like a regular human, Lena knows that the Otherworlder has the power to burn down her country on a whim, so she does the only thing she can. She befriends it. Can Lena stay sane when the fate of the world relies on her ability to lie, smile, and hold back her tears? Who knows.