Two surviving siblings escaped from a volcanic eruption and they try to go a safe place, except it's the complete opposite in Equestria. Years later from abuse & neglect toward a false allegation crime, the big sister is captured any bought her little brother some time to escape. The little brother cried in sadness of losing his last family member and wanted to end his life in order to find peace, until a calm voice stops him. It was the tree of harmony that he encounters and after some talk time, the tree has given him the elements before teleporting him to the mirror world. From there, he meets his adoptive loving family, but it's going to be very hard for him to adjust around almost every girl, including those that look identical to his abusers.

RGRE Girls.