[With just one word, I can take away everything that's bothering you.] Koo Hyo-seo, a new intern at Marine, a marine research institute that studies sea creatures. Hyo-seo, who had a hard time as a new employee, doing odd jobs due to the territorial nature of the staff, ends up taking care of a killer whale that everyone avoids because it's vicious to humans. To Hyo-seo, who had always been interested in killer whales, the aquarium where the violent and vicious killer whales were kept felt like the only refuge in her lonely and desolate intern life... "How great would it be if I could spend time like this every day, just the two of us...?" After mumbling to the killer whale like that, people at the research institute suddenly start getting hurt or going missing. A mysterious man appears before Hyo-seo, who is terrified. "So now we're alone?" Jet-black hair soaked in water, snow-white skin. Sparkling eyes. Like... is this what it's like if a killer whale becomes human? The man continues to hover around the lab and does not leave Hyo-seo's side... Who is this man, and what is happening in the lab? In the midst of increasing fear and an unknown labyrinth... "Why am I an animal? I am here next to you in human form." Why am I becoming more and more fascinated by this man?