Shuichi is tired of Kokichi's exasperating behavior, but when the mischevious leader steals the class's pet, it was just too much. Finally coming to a harsh confrontation, his scolding would take a turn he never expected.
After Kaede confessing her feelings for Shuichi, he managed to mess up letting her down gently & told her he had a boyfriend. He ended up asking Kokichi Ouma, who is already madly crushing on Shuichi, to pretend to be his boyfriend.