On an isolated island at sea, lanternkeeper Shen Yu numbered 734 lived a peaceful life, until a storm brought a mysterious visitor—Lin tide. Her arrival broke Shen Yu's entire understanding of the world. It turns out that this lighthouse is not a beacon for navigation, but a prison where memories have been stripped away, and he himself is both a prisoner and a guard. Lin tide claims to be able to help him find his past, but the price may be to destroy the false peace he relies on to survive. In the whirlpool of truth and lies, Shen Yu must make a choice: continue to be a carefree lampkeeper on an isolated island, or face the painful true self that may swallow him completely?