Writer-director Christy Hall’s “Daddio” is a smart and ambitious work featuring the type of intelligent character design missing from most of today’s films. Hall’s debut feature involves its audience in adult conversations that explore many different layers of the human condition, sustaining interest through honest and intelligent writing coupled with confident direction.

Dakota Johnson is a woman (credited as “Girlie”) who gets off a plane and gets into a taxi cab driven by Sean Penn’s “Clark”; the two strike up the normal conversation found between driver and passenger. Eventually, their back and forth takes a more personal route that captures the purity of organic human connection, something the world seems to have lost.

As the two characters build their rapport, Johnson’s character does not reveal her age or let Clark in on her real name. Beyond these privacy walls, Girlie proves to be game in answering most of her driver’s other questions.

Clark puts his passenger at ease with his easy going and instantly likable personality. He is just a working-class joe who has seen his share of life. As with many “cabbies,” Clark is almost a therapist to those who will open up and accept his inquisitive nature. At times, it may seem as if he is probing too deeply, as Girlie is a stranger, but it comes to pass that his intentions are honorable. In the wrong hands, Penn’s character could have been something dangerous or a tired, lecherous, cliché. With Christy Hall’s sharp and carefully crafted screenplay, Penn finds one of his most interesting characters in some time.

Dakota Johnson is stunning in her portrayal of a woman who is forthcoming about many things but still manages to keep enough of her secrets from her driver. Once she finally admits the reason for her mental strain (she is dating a needy married man, a secret Clark already figured out), the layers of the character unravel. While her lover sends her a barrage of frenzied sexual texts in the hope of getting himself off, Girlie seems to be more engaged with Clark. At first, she tries to concentrate on the messages, but her driver proves to be the intellectual stimulant she needs.

As an accident brings traffic to a halt, Clark and Girlie get as real as they can be. The two find strength and honesty in their “relationship” as Clark slides open the window that divides them and begins to open up about his own life. In his monologue, the interrogator becomes the subject, and the screenplay further explores the complexities of men and women, what trauma does to one’s psyche, the truths we live, and the lies we keep.

The two leads are superb. What may seem minimalist in the acting is anything but. Johnson navigates her monologues with supreme skill and tells us (and Clark) a lot by sometimes saying nothing, her emotions playing out in a look or a smile. The character is the illusion Girlie has created, but her truth is revealed through the poetry of Johnson’s performance.

Sean Penn goes deeper than Clark’s crude facade. While his questions are sometimes inappropriate, he is not an indecent person. Clark is a deep thinker and has learned from his time in the trenches of life. Doing his most complete work in years, the actor gets to the core of a man aching with loss but one who soldiers on. This is excellent work from America’s finest working actor.

Shot in sixteen days (rendered quite beautifully by the director of photography Phedon Papamichael), Hall has a gifted cinema with a film of ideas. The dialogue can be brutally honest, but there is a tenderness to the script and performances that makes the film complete.

It is rare that we are allowed to see real conversations on film. A good monologue or well-written dialogue between two characters can be as exciting as any moment in “Raiders of the Lost Ark”. Louis Malle’s “My Dinner With Andre” is certainly the best example, but Hall’s picture stakes its claim as an effortless excursion into the world of the human experience through dialogues.

Two people. One setting. A ride from JFK airport to midtown Manhattan. A world of emotions and soulful examinations. A striking directorial debut. “Daddio” is one of the year’s best films.