To save his lover struck by a mysterious toxin, a deep-sea merman is forced to transform into a human, step onto land, and take the name Adam Cole, infiltrating the massive Kraken Chemical Group to find the only antidote. Newly entering the human world, he is out of place everywhere, but accidentally meets Lily, an environmental officer investigating the truth behind her father's death. One comes for love, the other fights for the truth; amidst danger and suspicion, the two gradually stand side by side and step by step touch upon the huge conspiracy hidden behind ocean pollution. As Adam Cole's true identity becomes increasingly difficult to conceal, a chase spanning from the deep sea to the land quietly approaches.