An Yi (Zhou Yi Ran) is an assistant architect who works in Beijing, China. The reclusive Gao Ang (Patrick Shih) works as a piano tuner in Germany. One day, a freak accident somehow links their brain waves. Even though they have never met, suddenly they can communicate with each other by telepathy. Moreover, they feel the very same sensations as one another. For example, if one of them stubs their toe, the other one feels the pain just as sharply.
At first, they cannot stand having someone else in their “brain” with them – and sometimes go out of their way to cause pain to the other. But after a while, they start to support one another. When An Yi feels ill, Gao Ang tries to soothe her pain. When she needs to impress people by playing the piano in public, he steps in to help. She, in turn, tries to help Gao Ang come out of his shell. A bond begins to form between them. But what happens when the connection threatens to break? Can they really go back to being “alone” in their own heads again? And what would happen if they actually met in real life?