Mone will be playing Sakura Kazune while Moka will be playing Yumi. With regard to working with her sister, Mone said that she could relax and go all out in her acting and expressed her joy about their collaboration. When she read the original novel, she was so touched by the story that she was about to cry a number of times. With regard to her character, Mone said that there were many similarities between her and Kazune such as the pressure to do well as the elder sister and the jealousy towards Yumi because she also admires her younger sister's emotional strength and positivity.
On the other hand, Moka said that she was touched by the script which felt like a poem to her. In addition, as the filming was done in Hokkaido, it was a brand new experience for her and helped her to fit into the role easily. As for working with her elder sister for the first time, Moka said that it was an interesting experience to be practising their lines together at home and engage in a constructive discussion about how to act in the movie. She also described how Yumi's tendency to compare her piano-playing skills with her elder sister as something she could empathise with as since she is also a younger sister in real life.