1: Yamanami Crushes 
Feb 9, 2024
The Maritime Self-Defense Force submarine Yamanami collides with a U.S. nuclear submarine, crushing all 76 people on board, including its CO, Shiro Kaieda. Hiroshi Fukamachi, CO of the MSDF diesel submarine Tatsunami, becomes suspicious of the accident and analyzes the recorded data of the collision.