In this longitudinal observation, director and social anthropologist Soňa Lutherová presents an intimate portrait of a family in which one of the parents is transitioning. People who knew "R" perceived her as a happy woman. A Czech woman in her thirties, she moved to Sweden with her husband, psychiatrist Ivan. In their new country, the young couple bought a house and had two children. It seemed that their lives would continue in a predictable way. As a distraction from the routine, "R" chose an unusual hobby: she created a male alter-ego and started writing novels for LGBTQ+ audiences. "R" was happy but felt empty on the inside. She could only fill it by living out her true self. Things started speeding up and "R" began changing. "R" is now Marvin. And Marvin is a man. A HAPPY MAN tells an intimate story about a transgender man and his family. It encourages the viewers to consider different existential connections that concern each and every one of us.