The movie Jonathan revolves around the life of two brothers, Jonathan and John, who share a body but have separate personalities. Jonathan is the dominant personality who is responsible, organized, and dedicated to his job, while John is carefree, adventurous, and impulsive. Jonathan and John's condition is known as Dissociative Identity Disorder or DID.
Jonathan spends his days working for an architecture firm, coming home to their apartment, and writing notes to leave for John about what happened during the day. Meanwhile, John only emerges during the nighttime and spends his time going out and socializing with friends.
Jonathan has always accepted his condition, and so has their doctor who checks up on them occasionally. However, when Jonathan starts to fall for one of his colleagues, Elena, he becomes increasingly aware of how his condition is holding him back from living a different life.
As Jonathan starts to distance himself from their unique bond, John becomes increasingly frustrated and upset about his brother's behavior. The tension between the two personalities builds up, and the situation comes to a head when Jonathan decides to undergo a risky medical procedure to try and separate himself from John.
The movie explores themes of identity, individuality, and the bonds that uniquely connect siblings. It is a thought-provoking and emotional story that leaves the audience questioning what it means to have a sense of self and how far one is willing to go for personal freedom.