Stereopony - Stand By Me

Stereopony was a pop-rock female trio from Japan who formed in 2007 and disbanded in 2012. The group consisted of Aimi Haraguni (lead vocals and guitar), Nohana Kitajima (bass guitar), and Shiho Yamanoha (drums) and often had different lead guitarists sit-in for their live performances.
With the exception of one phrase in English (So I never let you go!) the song is sung in Japanese.
I found a translation site with both phonetic Japanese and English, much of the poetic meaning was lost, but it appears to be a friendship/love song about a boy releasing the girl from a relationship and to spread her wings and fly...