Kyoudai Shikkaku

A perfectly ordinary sister and brother share a casual conversation. The only unusual thing is that the brother is wearing his sister's sailor school uniform. As they chat, the sister also ends up wearing the same type of uniform. The brother becomes excited seeing his sister look different, and little by little, he can no longer hide his feelings. A climate of suspicion begins to form between them, leading to a tense and awkward atmosphere that threatens their sibling relationship.