Orito works part time at his mom's bar. One night, he sees his friend's brother Mitsuru with a group. After his group has left, Mitsuru comes up to Orito and asks him not to tell his brother that he was there. As Orito's "payment", Mitsuru kisses him. Confused, he affirms he will not say a word to the brother. The next time Orito visits his friend, Mitsuru opens the door and before he sends Orito up to Yuzuru with drinks, Mitsuru kisses him again and when asked if that was his reward, Mitsuru smiles and says nothing.
In the next scene, Orito is going to work when he bumps into his brother leaving the shop. Orito asks his mom if the brother borrowed money again and he had because "his girlfriend got pregnant". He gets into an argument with the mom that Mitsuru happens to intrude on when he comes in to get his drivers license. The mom leaves and Mitsuru hugs Orito and tells him that being a brother, there will be some imperfect areas. He says, "Like me, I'm imperfect too" and kisses Orito. They end up having sex and afterwards, Mitsuru says that even though his parents are always working and he's taken most of the responsibility for Yuzuru he sometimes wishes he could have someone to rely on. Orito says he wants to be that person.
Later, when Yuzuru and Orito are hanging out, Yuzuru mentions that his brother will be cooking for him since the mom will be working and happens to say how much Mitsuru pampers him. Orito is suddenly jealous of their close relationship and spills the secret that Mitsuru had been a regular at the bar and that he drinks a lot and with women. He immediately regrets it when Yuzuru is upset and that night, Mitsuru calls him multiple times but he ignores the calls. Mitsuru finally just texts him to come to his house Saturday since no one will be there.
Orito goes and immediately apologizes and is just as readily forgiven. They end up having sex and Mitsuru wants Orito to invite him over to his house since he's never been invited. Orito says it's only because his place is untidy and they make a date for Mitsuru to come the following Friday.
Some time later, they're shopping together at the supermarket when the brother spots them. He starts asking about what their relationship is, and Orito asks Mitsuru to wait outside while they talk a bit. Basically, Orito tells him that he'll not bother with what the brother does and tells him to do what he wants but to not talk to him anymore.
Mitsuru is heading up to Orito's place when he notices the lights are on. He remembered that Orito had to work but guessed he must have gotten off early. He announces his presence and gets further into the house when he sees the brother lounging on the bed. The brother starts talking and asks what their relationship is. Mitsuru says they're friends but the brother tells him that's not the case. He then says that he'd always liked Orito and that he's always wanted to be held by him. They talk some more when the brother gets agitated at what Mitsuru is saying, so he throws him down. They argue a bit more and Orito walks in. The brother leaves after saying he won't come anymore. Mitsuru is sad afterwards, thinking about how he's not a good brother. Orito comforts him and they have sex.
The last three bits are short little snippets. In the first, things have been tense between Orito and Yuzuru. With Mitsuru's slight nudge, the two of them make up. In the second, Mitsuru mentions that Orito's brother is a bit more proactive than Orito is and it would be good for him to be a little pushy sometimes. While Mitsuru is taking a nap, Orito comes in and ties him up and blindfolds him and they have sex. Afterwards, Mitsuru realizes it's because of what he said and Orito says it felt a little like he'd lost to his brother and Mitsuru tells him that's not the case and that thanks to Orito, Mitsuru realized his kinky side. Orito tells him to not show that side to anybody else. In the last one, they're enjoying a day off when Orito gets called into work as they're getting "in the mood". Mitsuru says he'll go with him - as a customer - and Orito says he can't because to have Mitsuru so close when he's like this is just as good as killing him. Mitsuru relents and says he'll stay home and make coffee and wait for his return so they can continue where they left off.
Yorokobi wa Hiza no Ue