Riiko Izawa has never had a boyfriend and she has been rejected by every boy she has ever had a crush on. When she returns a lost cell phone to an oddly dressed salesman she tells him like an idiot she wants a boyfriend when the "Cosplayer" asks her what she wants. So he directs her to his company's website as a way to thank her, but she has to not tell anyone. Riiko unwittingly ends up ordering a "figure" which will be her boyfriend with the intention of returning him after the free three day trial order. The way to boot him up is to kiss him, so when she kisses him, he wakes up. When he does so he's completely in love with her. He then asks what's his name? and she calls him "Night" since he's one of the "nightly lover" figure. After her three-day trial is over, Riiko finds that she cannot return her perfect mail-order boyfriend and is stuck with a bill for 100,000,000 yen (approximately 1 million USD)because she had added 100 things she wanted in a boyfriend (but each had costed 10,000.) The mysterious salesman, Namikiri Gaku, tells her the company will waive the bill if she will help them collect data about women's feelings, and data about their mental and physical structures in order to perfect future “Nightly Lover” models. Unbeknownst to Riiko, her next-door neighbor and childhood friend, Sōshi Asamoto, loves her which he strives to hide by frequently teasing her. He has promised her mother that he will watch over Riiko while her parents are away, and when he sees Riiko with her new "boyfriend," his jealousy creates the central love triangle of the series. Riiko must keep Night's true nature of an inhuman being a secret from everyone around her while struggling to decide if she loves Night, despite being a "figure" who seems to be developing true emotions, or Sōshi, who has loved her since childhood.