Mukai Naoya is in a relationship with Saki Saki, but another girl, Mizuse Nagisa, asks him out. He makes the unthinkable decision of asking them if they would be up for both dating him at the same time.
Naoya, Saki and Nagisa are now living together. Keen to learn more about Saki and Naoya, Nagisa gets into her phone and looks through her browser history.
Naoya, Saki and Nagisa search all around school for a place where they can eat lunch in peace, without anyone finding out that they are in a relationship.
Saki returns to Naoya's place and plays some games with Nagisa, who is utterly horrible at it. They notice that a gaming MeTuber seems to have the same uniform that they do.
Rika, who's outed as a popular MeTuber, insists on dating Naoya. When he rejects her, she decides to try to live at his home along with the other two.
Rika starts her not-so-laid-back solo camping life in Naoya's yard. Naoya and his girlfriends decide that enough is enough, and try to have her camping gear taken away.
Saki realizes Rika is serious about Naoya, and begins frantically looking for ways to keep her from joining their relationship.
Rika comes to hang out in Naoya and Saki's classroom, causing sparks to fly between her and Saki.
Saki tells Naoya that Rika's apparent crush on him is only the result of her being in heat. She insists that this is a real thing, and Naoya buys it.
As a way to clear the air after Rika kisses Naoya, he, Saki and Nagisa decide to go on vacation at a hot spring.
Nagisa spends her time on vacation with Rika to try to keep Shino from finding out that dating both her and Saki.
Nagisa had insisted on supporting Saki on the hot spring vacation, but when Saki confronts her about it, she begins to speak her mind.
