When he arrives at Astro Lodge to interview for the head chef position, Takumi Miyasaka finds a run-down boarding house instead of a fancy restaurant. Disappointed, Takumi nonetheless demonstrates his skills, much to the delight of the eccentric tenants. The happiest among them is the charming landlady, Mira Gotokuji, who falls in love with his cooking. On the other hand, Takumi falls in love with Mira. He decides to take the job as the breakfast chef at Astro Lodge and moves into Room 5.

Takumi soon notices strange things about Mira; she is hopelessly clueless about modern technology and Japanese food. In addition, Takumi hears an unfamiliar voice coming from Mira's room. What he does not realize is that Mira is an alien who has recently arrived from another planet on an important secret mission.