One accident, two suicides. Despite the many doubts, due to the lack of clues, these cases can only be resolved on the surface of "suicide", "accident". Behind the scenes murderer is carrying what kind of purpose to promote the progress of a case after all, who will be the next victim. You and your partner were assigned to investigate the case, and you entered the school disguised as a teacher and a student. Under the test of life and death, you must use the fastest speed to search for clues, solve the murder, restore the truth of the event. Whether it can fulfill its mission to uncover the truth behind this improbable series of crimes. If we can turn the tide and save more innocent lives. Your choice will determine everything.