I just read unpleasant comments below and I thought "geez! you people should at least acknowledge the genre before reading..."
It's Psychological. Psychological! it means -> usually deals with philosophy or a state of mind, nine cases out of ten the crazy kind, may contain some disturbing contents. The point is you shouldn't read sth you aren't ready for and then criticize it without a second thought even if you have a right to do so... I mean no harm. Furthermore even in yaoi there ARE girls, moreover quite often and still there are terribly surprised people... to whine about female lead character? why? honestly I don't get it. It's quite of refreshing. Not a next boring cliché.
It is really good manga with nice art, unique characters, plot and nice sex scenes and/but it is Psychological and you should give it a second thought. If you have no desire to do that - don't read it. There are 4 main characters bounded by difficult relationship, one of them is female. There's unexpected twist in the plot (or precisely two) that changes everything in their lives, that force them to face their true feelings and deal with unusual situation
it's their lover's deadly disease and the consequences of this disease including death herself.
As you can expect it's really hard for those guys since they're still teenagers. There's love, lust, admiration, jealousy, pity, concern, hate, anger, vengeful desire and friendship. They have different personalities
but the same lover. They must resolve many problems in their hearts and between each other. They're trying to find out her reasons as well as readers SHOULD because author left that without answer. We can only guess... The girl faced with deadly disease started to behave unreasonably and going out with 3 guys in the same time. But is that really unreasonable? She was very young but still had a death sentence, she knew she will never marry anybody nor have a children. She liked all of them but had no time to find out whom she likes the most. She treated each boy differently, special. She must've had a hard time but never complains. Well I don't dislike her. She didn't say anything to Orie the purest guy between those 3. I guess some people didn't even bother to think bout it... well nevermind.
In the end all of the boys desperately trying to easy the pain after lost of beloved one using sex. I like characters unique personalities, especially smart, sincere, tricky ladykiller Tatsumi who's trying to drawn in sex pleasure to forget... but he's aware it's pointless, that his pain won't disappear like that
As for me I wish for the hotter ending, it could be more background of the characters, but I do understand that the mangaka wanted to focus on deadly disease and it's consequences for living ones, by all meanings. This story is about it, bout pain & dealing with the lost of someone dear. You can also give some thought about boys' sex, it's different kind in the beggining, middle and in the end of story.
It's just not fair to explain here everything, use your brain and have fun 🙂