Admiral Yi positions his single flagship alone in the narrow strait of Myeongnyang, deliberately forcing his eleven reluctant captains to watch him engage the entire Japanese vanguard by himself. His Panokseon leverages higher deck elevation and broadside cannon barrages (Cheonja and Jija Chongtong) to smash through early waves.
When Kurushima dispatches a vessel packed with black powder to incinerate Yi's flagship, the captured scout Im Jun-young sacrifices himself from aboard the suicide ship. Jun-young's mute wife, watching from the cliffs, signals the fleet with her red skirt, alerting Yi in time to blow up the powder ship with cannons before contact.
As the tidal current abruptly reverses, creating a catastrophic whirlpool, Japanese ships lose steerage and crash into one another. Yi's flagship is trapped in the vortex until civilian fishermen use rope lines from small skiffs to physically pull the flagship free. Kurushima boards Yi's ship in desperation but is decapitated, his head hoisted to break Japanese morale. The remaining Joseon ships join the line, routing the surviving enemy fleet. The film concludes with Yi gazing into the sea, acutely conscious that future generations will likely forget the agony paid to secure their peace.