Domestic na Kanojo

Matsuo Fujii loves his teacher Hina. Trying to forget his feelings towards her, Matsuo goes to a concert with his classmates and meets a quirky girl named Rui Tachibana.

In a strange turn of events, Rui asks Naruto to sneak out with her and help her. To his surprise, their destination is Rui's house—and her request is for him to have sex with her. There was no love behind that act; she just wanted to gain experience. Thinking that it might help him forget about Hina, Naruto hesitantly agreed.

After this unusual encounter, Naruto now faces a new problem. When his father remarried, he had a new pair of sisters; Unfortunately, he knows these two girls too well. He soon discovers that his new siblings are none other than Hina and Rui!

Now living with both the teacher he loves and the girl he had his "first love" with, Naruto finds himself caught in an unexpected love triangle as he inches closer and closer to adulthood.