An accident many years ago which took place on a bus plays a big part in the present. When a man is killed on the bus, Conan learns of an event in the past involving the same exact passengers.
Conan intervenes to confront Touko about what she's doing. After that, Conan reveals that the murderer is Touko Natsume. She is the daughter of the murdered man named Kouhei Moritsugu from seven years ago and plans to take revenge on all the passengers present during that time. The motive is revenge that if someone else also help Komai (who was the previous bus attendent), and her father probably survive. She killed Okumura and Funaki (as their bus schedule don't match with the rest). First then attempts to kill the rest of the witnesses along with herself by tampered with the bus system. At first she attempt to kill Komai too for being the reason but after seeing that Komai go for her father's grave and thanks him every year she decided to not kill her. Conan tells Touko that Okumura was not involved in the bus accident seven years ago. When the bus was about to fall off the cliff, Conan rescues everyone with Elasticity Suspenders. After the bus has finally stopped, Touko is arrested.