Complex sentence: He convinces Mitsuha's friends Tessie and Sayaka to help him evacuate the village by staging a blackout and broadcasting a false emergency alert, but realizes that Mitsuha would be in his body at the grotto and goes back to find her.
Split into simpler sentences: He convinces Mitsuha's friends Tessie and Sayaka to help evacuate the village by cutting the power and broadcasting a false emergency alert. He realizes that Mitsuha must be in his body at the grotto and goes back to find her.