During his childhood days, Tsurugi and Kiyou were best friends since daycare and had been together since then. Kiyou had love feelings for Tsuguri but after realised, Kiyou was mean and called Tsuguri gross without knowing that they'll not be able to see again. Years after, during the las days of high-school, Tsuguri appears in fro t of Kiyou and all those feelings that he desperately tried to suppress are now on the surface once again.
OK, I really like this story despite the fact that it's super toxic. Tsuguri's feelings and Kiyou's feelings were the same but their actions were so different. One was super obsessive and the other living in denial just to keep "normal".
Doushiyoumonai Renjo