[With just one word from you, I can remove everything that troubles you…] Goo Hyo-seo, a new intern at the marine research institute 'Marine', begins his career under tough circumstances. Facing senior employees torments and constantly being bossed around and treated poorly by other staff, Hyo-seo is assigned to care for a killer whale/Orca that everyone avoids due to its aggressive nature toward humans. To Hyo-seo, who has always been fascinated by killer whales, the aquarium where the violent and vicious killer whale were kept felt like the only refuge in hours lonely and desolate intern life… "If only I could spend time like this, just the two of us, every day… How wonderful would that be…?" After murmuring these words to the orca, strange things begin to happen at the research institute. People start getting injured or going missing. A mysterious man appears before Hyo-seo. "Now it’s just the two of us, huh?" Dripping wet black hair, pale white skin, and piercing eyes. It’s as if… the killer whale had taken a human form. The man lingers around the research institute, never leaving Hyo-seo’s side. Who is this man, and what is happening at the research institute? Amid growing fear and an unsolvable mystery… "Why would I be an animal? I’m right here next to you in human form." Why is Hyoseo becoming more and more captivated by him then?