This takes place around the middle of season 8, after School Daze but before School Raze.

The School of Friendship has been a great success for the mane six and all the students. It had a rocky start and was risked for getting unaccredited, but the group pulled through and over time, more ponies supported the school.

However, when the young six found something in the school they never thought they’d see, a normal day that should be filled with giggles and fun lessons took a turn for a more uneasy environment and suspicion arose between the peers.

It seems that somepony was trying to destroy their hard work and their fun paradise of friendship and diversity. The only thing missing, is the one thing everycreature was asking:

“Who did it?”

Edit on 7/4/2018: Got into popular stories! Thanks guys!