So, Itou Makoto, the main protagonist, loves a girl, so he is introduced to her by another girl, who also loves him. The basis for a love triangle. However, School Days takes this concept to a new dimension.
The guy who loves the girl is brain dead, but eventually the girl loves the guy more than the guy loves the girl, so then the guy who does not break up with the girl starts liking the other girl who introduced him to the first girl, and then they become a couple, but since nobody knows that he was ever with the first girl they think he is with the second girl, and the first girl knows none of this so she keeps insisting she was always with the guy, and this fact gets her into a lot of problems. The guy is now with the second girl, and additionally he has his eyes set on many other girls because he has no self control, so then during a school event a girl who used to go to his middle school confesses to him and they go inside a break room where they do the chakalakalaka but what they don't know is, they were being recorded. So after that a friend of the second girl asks the guy to swear loyalty to the second girl because she needs to leave the country and the second girl will have no friends left, which would make her very sad. The friend also loves the guy, but the first girl finds out and at this point the first girl becomes depressed. So then after cheating on the girl who he cheated on the first girl with multiple times many other girls are interested in him because of his sudden popularity. He thinks everything is going so well but eventually, the second girl finds out he was cheating by seeing the recording, and has had enough so she tells the guy in front of everyone that they did the chakalakalaka without protection which was supposed to make the guy feel sorry for her and stay with her, but the guy decides its not his fault so he keeps doing his thing, and after his act falls apart he meets the first girl so she is not depressed anymore, they go back to his house and the second girl finds out, so then she becomes depressed, which causes her to become even more depressed than the first girl, who says that the first girl was selfish because her friend was the one who liked the guy but she swapped seats with her friend to get closer to the guy, then later introduced the first girl despite herself being in love with said guy. The first girl catches on that the second girl lied about the chakalakalaka and tells her to go to a medical clinic to support her unborn child however the second girl does not do this and her mind by this point is completely broken so she goes to the guy's house and ends him. Afterwards the first girl finds out and tells her to go to the school roof where she brings the corpse of the guy, and accuses the second girl she lied about the child, then proceeds to end the girl, then disproves her lie through makeshift surgery. The first girl who is still in love with the guy takes the guy's head and carries it forever.
