Shen Zheng, a top modern structural engineer, unexpectedly finds himself transported to a desolate prehistoric island. Just after waking up, he is mistaken for a sacrifice by the Black Reef Tribe and tied to an altar to be offered to a giant prehistoric crab known as the Evil God Who Swallows Islands. At the brink of death, he uses his professional knowledge of mechanics to identify the monster's weakness and escape. Using engineering techniques such as the rolling-log principle, ice-and-fire quenching, and giant levers, he leads the tribe to slay the giant crab and defeat the plundering Mad Shark Tribe. Just as he leads his people in building a cross-sea bridge to conquer the Sea of Death, a colossal shadow far greater than the crab emerges from a deep-sea whirlpool, and a terrifying roar echoes across the ocean.