Heiji won a bet in the previous episode and so it's decided that they're all going to the high school baseball finals in Koshien Stadium. But there is a mysterious guy willing to commit a suicide bombing there. This incident just puts more stress on Conan and Heiji, even though they came to a ball game for amusement and relaxation. The unknown person gives them a chance to stop him, however. Heiji and Conan are both struggling to crack the codes, sent by the mysterious man, before the bomb goes off. Earlier, Conan and Heiji witnessed the person walk by them and they thought he dropped his cell phone, when he purposely left it there to "play the inevitable game" with them, consisting of cryptic text messages. In order to solve this case and save countless lives, Heiji and Conan would need a lot a background information dealing with America's favorite pastime, baseball.