WARNING: The following contains spoilers for Episode 4 of Girlfriend, Girlfriend, "Girlfriend and Girlfriend" now streaming on Crunchyroll.
Naoya has himself a pretty impressive harem already in Girlfriend, Girlfriend, with the fun and endearing Saki and the dedicated Nagisa. But as of Episode 4, there could possibly be a new member joining this multi-person relationship. Naoya had just settled things with Saki after her brief absence in Episode 3 and things are just getting back to normal when a new girl enters their lives: Rika Hoshizaki.
In the first half of Episode 4, Nagisa and Saki actually spend some time with each other while Naoya sleeps. They bond while playing the same video game on their phones. After having a great time playing together, Saki suggests they watch some game vloggers on MeTube. Nagisa shows her one of her favorites, named Milika, and Naoya recognizes the school uniform in the background of one of her thumbnails -- it belongs to their school.
Sometime later, the three of them eat lunch at their secret spot in the gym storage room at school. As they sit there discussing how this famous MeTuber goes to their school, their private time is interrupted by someone trying to get into the room through the open window: Rika. At first, Rika is all about the weirdness of the three of them eating lunch in secret. She quickly draws the conclusion that they are a threesome and Naoya can't even think of a cover story.
But then Saki and Nagisa start asking questions. Nagisa asks if she's Milika, the famous MeTuber. Rika tries to deny it but when Nagisa pulls up the screenshot of their school uniform, Rika is caught, bringing both parties to an impasse. They all know each other's secrets. Turns out, Rika was sneaking into the gym storage room because she was worried people at school would recognize her.
Maybe because she's caught in a bind, Rika makes a massive decision and announces that she's going to be joining their little harem as Naoya's new girlfriend. This rash decision could also be due to the fact that Naoya boldly declared he wouldn't share her secret, even if she decided to share his. Becoming his newest girlfriend is a win-win for Rika because she will be with a decent guy and her secret will be protected.
But will Naoya agree to this? More importantly, will Saki and Nagisa? It's known that Nagisa would do literally anything to be with Naoya, but Saki might not be able to handle yet another girlfriend in the mix. The delicate balance that Naoya, Nagisa and Saki have struck is facing the possibility of destruction.