Mouri, Ran, and Conan are waiting for the train when they notice a group of people leaving work on a Sunday. Once they boarded the train the group finds their co-worker dead in an empty train car. After all three are presented as possible suspects Conan notices a couple of clues, there is a mark on her ear and a line on her arm. Before long Conan stuns Mouri and reveals who did it and the evidence used to prove their guilt,