After translating the lyrics, the song seems to be about someone unsure about their feelings or afraid to confess to another person and watching them from afar. I like the rock sound, mixed with some modern elements and the wooden (maybe Kolberg?) xylophone.
This banger just appeared to me as an ad, dang it, RU-vid TV didn't give me any information. I spent almost an hour to find it again, I succeeded just cuz' my friend who speaks Japanese.