Right after Gonta's execution, Kokichi starts planning ahead and tries to figure out who the mastermind is. Stumbling upon some disturbing evidence of one of the few people he put even the slightest amount of trust in.
Dipper's family never really liked him. He was always insulted and made to work. It got worse when the twins go to Gravity Falls. However, Dipper has a secret that nobody knows and one day he's had enough... (Mabel and Dipper are 16 in this)