Engaged to the Unidentified - Season 1 Episode 4 She's Just a Pervert

The morning after learning about Hakuya, Kobeni ends up with a fever due to her weak body. As Benio informs Mashiro and Hakuya about what she told Kobeni, she blames herself for Kobeni's accident back then, as she had Kobeni take her place alongside Hakuya so she could go and play. The next morning, Kobeni opts to stay at home alone whilst the others go to school, though Mashiro comes back to help her as soon as school ends, where Kobeni shows her the scar she received back then. The next morning, as Kobeni starts feeling a bit better, Hakuya suddenly rushes out of the house when he notices Kobeni struggling to face him properly. Kobeni catches up to him and states that, even though she doesn't remember anything, she owes him her thanks, becoming awed by his smile. Later that night, Mashiro and Hakuya receive a letter from their family, saying they will be sending someone to check up on them.