A compelling character-based drama that reveals the interior life of a young trans man over roughly 24 hours in New York City, “Mutt” follows Feña (Lío Mehiel) as he tries to navigate a series of events that would be stressful for anyone. Piling on setbacks that specifically challenge someone still working out how to reintroduce himself to old friends and family members, writer-director Vuk Lungulov-Klotz — who is also trans — makes audiences acutely conscious of Feña’s emotional state at every turn. “Mutt,” which premiered at the Sundance Film Festival, sees the first-time helmer creatively using the medium to illustrate how small incidents can chip away at a trans person’s self-confidence and the strength it takes to stay true to that identity.

Feña’s day starts simply enough, focused on trying to borrow a car to pick up his Chilean father (Alejandro Goic) from the airport. Before long, it becomes a day from hell. He gets locked out of a friend’s apartment. His teenage sister (Mimi Ryder) decides to skip school, experiencing her first menstrual period while spending the day with him. As brothers go, Feña’s uniquely qualified to help her handle the situation. In fact, the night before, Feña hooked up with an ex-boyfriend (Cole Doman), sparking a pregnancy scare that also calls for a visit to the pharmacy, where he hopes to acquire a morning-after pill for himself.

Could so many problems befall a single person in such a short period? It’s a tad unrealistic, perhaps, but easy to forgive, as Lungulov-Klotz cleverly demonstrates how seemingly mundane activities can be uniquely complicated for a trans person like Feña — as when a bank clerk misgenders him and refuses to cash a check that doesn’t match the name on his driver’s license. Each encounter feels genuine and moving, such that everything resonates emotionally. Feña’s identity is constantly on his mind as these mishaps occur. It’s also on the minds of everyone he interacts with because his transition has affected them too.

Lungulov-Klotz has an authentic grasp of New York City — its streets, buildings and locally owned businesses. Each of the locations that Feña visits rings true as a real place and not a film set. Collaborating with cinematographer Matthew Pothier, they create a vision of the city that’s unlike what is usually presented in so many American indies, giving audiences images that are tangible and instantly recognizable, rather than trying to show the city in attractive light.

Mehiel, who’s in almost every scene of the movie, carries it with aplomb and is always immensely watchable. However their performance becomes even stronger when they are playing off other actors with whom they have noticeable chemistry, particularly the charismatic Doman and the heartbreaking Goic.

In an affectionate but also palpably sensual scene, Feña reconnects with his ex-boyfriend, who last saw him before the transition. Fraught with both tension and heat, the encounter begins with discomfort as Feña tries to avoid revealing his body. But as the lovers recall their strong physical connection, the moment becomes as much about discovering Feña’s new identity as it is about two lovers falling into old habits.

There’s a charge to this interaction, which is sensitively filmed and portrayed with tender affection by Mehiel and Doman. Beautifully shot and romantic in its setup, as the two lovers escape the rain to seek shelter in a laundromat, the scene becomes a transfixing moment of movie magic, a modern twist on those larger-than-life moments from the golden age of Hollywood that mixes old-fashioned romance with a sexuality that defies labels.

In queer narratives, the gruff unapproving parent is commonplace. “Mutt” presents something different: Feña’s father is skeptical and questioning of his son’s transition, but also supportive. Adding complexity to the characterization is the culture clash between a traditional Chilean father and his American son. Goic toes the line between those differing states so well, elevating his scenes with Mehiel and making them the most resonant of the whole endeavor.

While Feña’s journey may contain some contrivances, the way this young man adapts to each predicament feels authentic and emotionally potent. That’s a testament to Lungulov-Klot, who succeeds in placing vivid characters in slightly heighted situations — amplifying our connection in the process — without sacrificing the sense of realism that makes “Mutt” so relatable.