Izawa Riiko is a young office lady, who day-dreams a boyfriend all for herself. While she deals with her hopeless love for a man in her company, destiny crosses her path with the name of "Kronos Heaven", a company with a great project to fulfill: the first robot-boyfriend of the world.

Before telling the world about this new commercial jewel, the Kronos Heaven company decides to test its baby, Night Tenjo, the perfect male humanoid created to be devoted and loyal to his lover. The choise for the lucky woman fell upon Riiko, who, overwhelmed by the events, takes part in a 5-day free trial.

 At the beginning, Riiko is very skeptical about the use of Night and she sees him only as an home appliance. One day, Ito Mika, Riko's best friend, reveals her true personality: she likes conquering other women's boyfriends. When she mistakes the relationship between Riiko and Night, she decides to pull away Night from our heroine and she kisses him.

Kisses are very dangerous tricks. When a woman, who is not the girlfriend-mistress, kisses the robot-boyfriend, his inner system is resetted and re-programmed for the new girlfriend. The different behaviour toward her convinces Riiko to buy Night from the Kronos Company. The bad adventure ends with Riiko kissing Night who, strangely, has not forgotten her after the new start.

 Slowly, Riiko finds herself falling in love with Night, but a new suitor enters the scene. He is Asamoto Soshi, a young executive at Riiko's company who has feeling for her.

Who will Riiko pick?

Contents are Claudia