Kuzu no Honkai

A high school couple, Mugi and Hanabi, maintain their relationship by keeping a mutual secret—each is in love with another person. The series includes additional chapters and several one-shots titled "Nyan Nyan Prelude," "Nyan Nyan Serenade," "Nyan Nyan Oratorio," "Nyan Nyan Cantata," and "Nyan Nyan Andante."