Scheduled for routine military exercises, Kadomatsu and the crew of Japan's newest and most modern battlecruiser, Mirai, are ready to test out the ship's state-of-the-art AEGIS systems. Instead, they find themselves transported back to June 4th, 1942 - date of the crucial Battle of Midway, where the Japanese fleet was dealt a crippling blow. But when an overzealous Kadomatsu rescues one of the battle's victims, Kusaka, from a sinking Zero Fighter, the Mirai's fate is sealed. They are forced to fight a U.S. submarine in a battle that should never have occurred, and the crew pledges not to do anything to alter history further. But the flow of history may already be diverted…