Mirai, the Japanese Self Defense Force's latest Aegis guided missile destroyer is a remarkable vessel based on the Kongou class. The ship is manned by a fresh and inexperienced crew led by Captain Umezu Saburo and Executive Officer Kadomatsu Yosuke. During a regular training session, the crew of Mirai is hit by an unexpected storm that wreaks havoc on their navigation systems. To their surprise, they find themselves transported back in time to a significant day in history - 4th June 1942, during World War II's Battle of Midway. The crew decides to preserve the timeline and avoid any significant alterations as they watch history unfold. However, when they come across a mortally injured Lt. Commander Kusaka Takumi, Kadomatsu's compelling desire to help results in unforeseen outcomes that could alter the course of history.