Mori's "Twin Sister" [OHSHC]

PSA! THIS IS A REWRITE OF A STORY I WROTE WHILE I WAS IN HIGH SCHOOL!! PLEASE IF YOU WOULD LIKE TO READ THAT FIRST, IT IS COMPLETED

Rina and Mori have been together since birth, so they think, and got separated when Rina went to go live with her aunt and uncle in England to get a better education.
Rina returns home to finish secondary school, she is so excited to be with her brother again after being gone for 10 years.
When they think all is well and perfect as it should be, things take a turn for the worst.
What happens??
You'll have to read to find out :)