Riddle Story of Devil Episode 4 English Dubbed Episode Title:What Comes Suddenly and Never Leaves?.Episode Description:As Class Black undergo mid-term exams, Tokaku and Haru hear from Chitaru Namatame, who is often seen with Hitsugi Kirigaya, that she is not targeting Haru, as she joined the Class Black for a different reason, before later hearing an urban legend from Nio about a hidden room in the library. Upon returning to their room, Tokaku and Haru discover another advance warning, also discovering some bombs has been planted in their freezer. The culprit this time around is Kōko Kaminaga, an assassin specialising in explosives who was exiled from her organisation after her teacher was killed in a failed bombing attempt, which Kaminaga herself was responsible for, as she had set the timing that the bomb would go off at too early, which killed her teacher, instead of their target. Despite knowing the danger, Tokaku accompanies Haru to the library and manages to locate the hidden room from Nio's rumors. There, Tokaku narrowly manages to protect Haru from a hidden bomb and pursues Kōko, who wanted to use her wish to quit being an assassin, managing to disarm her and stop her attempt, leading her to be transferred out of Class Black the next day.