In a past life, a global tsunami caused sea levels to surge by five kilometers; bodyguard Lucas, while attempting to rescue his boss Blake and CEO Cooper, was betrayed and pushed into the sea to be fed to the sharks. Reborn one month before the disaster, he awakened a "Vessel Evolution System" and resolved to rescue only high-rated survivors. When the tsunami struck, Lucas built a raft to save Evelyn—a kind-hearted employee with an "A" rating—causing his raft to evolve into a kayak. The pair then rescued Mia—Evelyn’s "A+" rated best friend—from a flooded shopping mall, upgrading their vessel to a speedboat. Returning to the rooftop, Lucas humbled the arrogant Cooper before taking him in, causing the speedboat to evolve into a three-deck yacht. When Blake returned seeking revenge, Lucas repelled him and left him stranded at sea. Later, a wealthy heir named Leo and his gang coveted the yacht, leading to a standoff where Lucas forced a game of Russian roulette; after Leo shot one of his own companions, Ophelia—a stunning beauty with an "S" rating—realized his true nature and defected to Lucas's side. The yacht subsequently evolved into the *Savior*, a massive ten-thousand-ton ocean liner. Lucas assigned roles to the group—tasking Ophelia with cleaning duties—and activated the radar to set sail in search of more high-quality survivors.
