Friends and AcquaintancesEdit
Sachi and Tohko are friends. Sachi cares about Tohko and was worried if Kakeru would do anything weird to Tohko. Sachi is very protective of Tohko, and when Hiro's sister asks her if it was her boyfriend that gave her the pendant that she was wearing (that was given by Tohko), she says that it was not given to her by her boyfriend, but by the person that she loved. This suggests that Sachi harbors feeling to Tohko that exceed the realm of platonic friendship. In episode 10, Sachi confesses to Tohko and Hiro. And sachi told Tohko that remained friends.
Sachi didn't trust Kakeru enough to let him and Tohko meet by themselves. She has mentioned to Tohko about Kakeru though, that she doesn't think that he's a bad person, and even remarked that he was cute. Her distrust for Kakeru mostly stems from her strong feelings for Tohko. She later states to Hiro that she hates Kakeru for breaking up their group.
Hiro has a crush on Sachi, but she doesn't seem to recognize it much until episode 3 when he stays with her while the rest of their friends find water for their lunch. When Yuki leaves to go find Tohko and Yanagi, Hiro asks if she like yakisoba and cooks it for her. While he cooks it, she watches him and he tells her that she "looks like a doll" while she reads, but Sachi misinterpreted it, asking if it was a poem. He then agrees it is. Later, he tries to confess to her, but she ends up giving Hiro a book, for "always taking care of her." In episode 4, Hiro comes over to Sachi's house to return the book, but ends up staying and reading along with her.
He then musters up the courage to ask her if she wanted to see a movie aicbout the book, to which she agrees to. Later, when Touko is at Kazemichi, she notices that Hiro isn't there, with Hiro's grandfather telling her that he's on a date. In episode 5, Hiro and Sachi again are reading at Sachi's house, in her room. She sees Touko come up to her house, with Hiro blushing and being embarassed. Before she leaves to greet her, she looks back at Hiro and smiles at him. It is later shown that he escapes through her bedroom window outside, so Tohko wouldn't see him.
In episode 7, when Sachi is being taken in for tests again, Hiro comes to visit her, however meets her mother, also. Sachi introduces Hiro as her boyfriend, making Hiro blush and Sachi's mother smile. On his next visit, he brings her cookies and Sachi's mother tells him to make sure that she's okay, calling him, "Mr. Boyfriend." Thy appear to currently harbour romantic feelings for each other.
In episode 10 Sachi confesses to Tohko and Hiro. Hiro accepts that feelings of Sachi continues its Sachi Fiancee and later apologizes for what happened.