Read the chapters up to 19 in Japanese, but I skimmed the last few since I got more and more put off by it. PLEASE, PLEASE read this spoiler if you are not into this genre: NTR and stupid attempts at cheating/getting a trio relationship.
Here is a rather LONG summary of the spoilers:
REMEMBER, I read this in Japanese so the names are Japanese as well. Joy is Megumi, Hye-Yeon is Sana and Namsu is Makoto. This isn't really a spoiler, so I'm just leaving this out here.
Since the first some chapters are free, I won't cover those. Makoto and Sana meet up where Makoto finds out Sana has been sleeping around abroad. The two of them learn of each other's feelings for Megumi in the process as well. Makoto is challenged by Sana, who guarantees that she will make Megumi fall in love with her.
Shit happens, and the weirdo chick with glasses who can supposedly sense "love in the air" (her name is Shiori) confronts Makoto, who makes the latter realize that she is indeed, in love with Megumi. Later on, Makoto is down with a fever and has this elaborate dream of dating Megumi and just being lovey-dovey with her (including kissing), which turns Makoto on greatly. When she comes to, she is immediately depressed over it being a dream, but masturbates to her fantasy. This scene is a lot more angsty than how I'm describing it by the way.
Later, Shiori goes to confront Megumi about this love triangle and FORCES her to realize that Megumi's ignorance is making Makoto feel absolutely miserable and is creating turmoil between Makoto and Sana. On the way home, Megumi finds an ill Makoto wandering around the streets.
Makoto, still in a daze due to her illness, forces a kiss onto Megumi, but passes out immediately after. Makoto is then taken home by an ambulance, but it's nothing serious. The next day, Megumi meets up with Makoto before school, where she acts like nothing happened. However, Megumi soon takes Makoto out of the classroom and they sit together and talk about the event from the night before. Megumi reveals she knows of Makoto's feelings and they confess to each other (!!!) ... and they start going out after they get a kiss in.
Megumi tells Sana about their new relationship, and Sana is immediately heartbroken, but urges Megumi not to tell anyone else about their relationship. Megumi takes this as a sign of protection and agrees with her. After all this, Megumi and Makoto get along well, Makoto is feeling great about running again and the two go on a date, which at the end of the day, leads to Megumi going over to Makoto's house. Oh yeah, and during the date, the girls buy each other shoes as presents.
They end up sleeping on the same bed, but nothing beyond that happens really. The next 3 or 4 chapters are ALL about Sana and her childhood with Megumi, which I seriously did not bother to read since I was more on team Makoto. Sana ends up crying over the phone to Megumi and Megumi barges into the room and that's where the latest chapter ended.
I looked up more spoilers from 4chan and it turns out, Megumi ends up with Sana, but she tried to get Makoto and Sana to be friends with each other (this failed miserably). She supposedly cheats on Makoto with Sana, but in a way where she tried to link all three of them together.