It was uploaded the onto both Nico Nico Douga and YouTube on October 26, 2013, since then, it has entered the Hall of Fame, and reached over 9 million views on Youtube. It's considered one of Len's most notable songs.
It's part of Honeyworks' Confession Executive Committee Love Series and it tells the story of Setoguchi Yuu and his younger sister, Hina. The song starts on a Sunday morning, with Yuu brushing his teeths while noticing that Hina was putting on makeup, thinking that she was just a kid and that her getting to this age felt kind of wrong, wondering if she had a boyfriend. Despite being embarrassed to admit it, he tends to spoil her, always loses to mischievous smile or crying face. He would usually let her borrow his favorite parka as a roomwear. In their childhood, Yuu acted distant, not wanting her around when he was with his friends and not allowing them to walk hand in hand. When she was quiet for three days in a row about breaking his favorite toy, Yuu got mad at her. Now, he wonders if he'll honestly be able to say "It can't be helped." instead. He hopes that things won't ever change between, always arguing, yet always there for each other, stating that he'll always be by her side, watching over her. In the end of the song, Hina's shown crying while looking at a photo, which is later revealed in Ima Suki ni Naru. to be a picture of her and Koyuki, on his Middle School graduation day. Thinking that her crying face isn't so bad once in a while and wanting to cheer his sister up, Yuu takes her by the arm and finally says out loud that she's precious to him.