Shuichi Saihara had escaped the killing game with his friends and now is living his life as newest Ultimate Detective. Throughout his 3 years there, He has solved over 200 cases since being back. Although, He recently got a case file that directly states for a duo. As he solves most cases alone and his uncle is solving another case somewhere else, he needed to ask one of his friends to go on a crime-filled journey and solve some cases.