Fact1: Gordon sees aspects of himself and own awkward childhood in boy, Fact2: Dennis sees something of kindred spirit in David, Fact3: David is cleared to take Dennis home, Fact4: Lefkowitz sets up review of case, Fact5: David 's voiceover tells about parallel of children
Output: David Gordon, a popular science fiction author, widowed two years prior as they were trying to adopt a child, is finally matched with a young boy, Dennis. Initially hesitant to adopt alone, he is drawn to Dennis because he sees aspects of himself and his own awkward childhood in the boy. Dennis suffers from the delusion that he is from Mars. He protects himself from the suns harmful rays, wears weights to counter earths weak gravity, eats only Lucky Charms, and hangs upside down to facilitate his circulation. He refers often to his mission to understand earth and its people, taking pictures, stealing things to catalog, and spending time consulting an ambiguous toylike device with flashing lights that produces seemingly unintelligible words. Once David decides to adopt Dennis, he spends time getting to know the boy, patiently coaxing him out of the large cardboard box he hides in, which becomes a metaphor for coaxing him out of his shyness and into new situations. We wonder if Dennis sees something of a kindred spirit in David that draws him out. Soon, David is cleared to take Dennis home and they meet Davids dog, Somewhere. In Denniss bedroom is a projector of the solar system that he pronounces inaccurate. With the help of Davids friend Harlee and sister Liz, David tries to help Dennis overcome his delusion by both indulging it and encouraging him to act like everyone else. Dennis attends school but is quickly expelled for repeatedly stealing items for his collection. David tells Liz, though its not clear if hes being genuine or sarcastic, that perhaps Dennis is from Mars. Meanwhile, Davids literary agent, Jeff, encourages David to finish writing his sequel book, already commissioned, which is due soon. David struggles to make time for writing but is regularly pulled into dealing with Denniss issues. Finally, David hunkers down to write when a flash from Denniss Polaroid camera catches him offguard and he accidentally breaks some glass. David snatches Dennis up and carries him across the room. Dennis, upset by Davids abrupt action, fears he is going to be sent away. David explains that he was just worried hed get cut by the glass and that he loves Dennis more than his stuff. Assuring him that he will never send him away, he encourages Dennis to break more things. They move to the kitchen and break dishes and then spray ketchup and dish detergent at each other. Lefkowitz, the decisionmaker from Social Services, appears in the window and discovers the mayhem. He rebukes David and sets up a review of the case. David encourages Dennis to be from Mars only at home; he has to be from Earth everywhere else. Dennis passes his interview by saying he was pretending and continues in Davids care. Later, David, now Denniss adopted father, tries to insist that Dennis acknowledge being from Earth, to which Dennis responds with hurt and anger. David leaves Dennis with Liz to attend the reveal of his new book, which is supposed to be the sequel to his first book. David confesses to Tina, the publisher, that he has not written a sequel, but rather a new book titled, Martian Child, about Dennis. In her fury, Tina makes a scene at the party, but takes the manuscript as David leaves to be with Dennis. Meanwhile, Dennis has walked away from Lizs house, together with his suitcase of earthly artifacts. When David arrives and finds the police at Lizs house and learns the boy is gone, he remembers the place Dennis had identified as where he was found. David asks Harlee to drive him to the location, where they spot David high up on the outside ledge of the museums domed roof. David climbs up to where Dennis is as the police and Liz arrive. Dennis identifies a bright searchlight in a nearby cloud as someone coming to take him home, but David tries to assure him that its just a helicopter. David pledges his love for Dennis and assures him that he will never ever leave him. Eventually Dennis gives in to trusting David and the two embrace. Davids voiceover tells about the parallel of children who come into our world, struggling to understand it, being like little aliens. As we zoom in on Tina reading the manuscript aboard an airplane, we realize these are words from the book. Tina is crying.