In his dream, Masaru (played by Takashi Okamura) witnesses a traffic accident. After waking up, he goes to the place in his dream based on his vague memory. The scene in front of him shocks him - it is exactly the same as his dream: the perpetrator fled after the accident and disappeared. The police went to the house of a suspect, a woman named "Lan" (played by Lee Na-young), and arrested her while she was still asleep. Lan firmly denies being the perpetrator of the traffic accident. Later, it was discovered that she suffered from severe sleepwalking. When the condition flared up, it seemed to split into another personality, forgetting everything she did after waking up. More incredibly, Masaru realizes that the actual mastermind behind the scenes is himself! Because his dreams can control the woman's actions, whenever Masaru dreams, the woman does some strange things, and they become more serious one by one. Dreams and reality overlap, and Masaru and Lan gradually can't tell which is a dream and which is real life. The two people appreciate each other and even develop feelings of love, and seem to slowly become one person with the same will...