Robot maker, Kronos Heaven, finally develops "Night Tenjo", the perfect male humanoid programmed to be devoted and completely loyal to his lover. The company chooses temp worker Izawa Riiko to take part in a 5-day free trial. At first, Riiko only sees Night as a household appliance. But when she finds out how deep Night's devotion to herself is, Riiko finds herself falling in love with him. Joining the love triangle is Asamoto Soshi, a distinguished young executive at her company who has feelings for her.
When they were middle school students, Aihara Eiji and Bessho Naohiko attended the same school, and they were best friends. One day, Eiji’s childhood friend Shiosaki Izumi transferred to their school. Eiji had feelings for Izumi, but he never told her how he felt. Naohiko though confessed his feelings to Izumi and they became boyfriend and girlfriend. Now, all 3 are first-year high school students and attend the same school. There, they meet Fujimura Koharu, who begins to have feelings for Naohiko, Senami Taichi, who is a member of a band, and Ikezawa Mizuho, who is a literary girl and likes Eiji.
Eom Da Da is a special effects make-up artist who has been secretly dating Ma Wang Joon, an A-class actor, for 7 years. After a sequence of incidents that damaged Da Da's belief in her love, she decides to break up with Wang Joon. With a heart barely healed after the breakup, she ends up meeting Young Goo, a humanoid robot programmed to be a perfect boyfriend. Young Goo begins to develop human emotions and gets involved in a love triangle with Wang Joon and Da Da.
