Hae-Gwan's (Lee Sung-Min) daughter Yoo-Joo (Chae Soo-Bin) is missing. People around him tell him that his daughter died in the fire that took place at a subway station in Daegu, but Hae-Gwan refuses to believe she is dead. To find Yoo-Joo, he goes everywhere and anywhere. One day, he receives a phone call that the caller saw Yoo-Joo on an island. Hae-Gwan goes to that island, but he can't find her there. At night, Hae-Gwan sits on rocks by the sea. He sees a light fall into the ocean and he is then swept by big waves. Hae-Gwan then finds himself on the beach. He sees something unusual and first believes it is a landmine. It turns out it is actually an AI satellite robot which saves every conversation made on a phone. Hae-Gwan thinks he can find his daughter with the help of the robot. He names the robot Sori ("Voice").