David Gordon (John Cusack), a popular Science Fiction author, lost his wife Mary when they were trying to adopt a child. Two years later, David is finally matched with a young boy named Dennis (Bobby Coleman). Socially awkward, Dennis believes he is from Mars and only goes outdoors when under the cover of a large box to block out the sun's harmful rays. Although initially hesitant to adopt a boy by himself, David recognizes a part of him in Dennis and slowly coaxes him out of the box and into his home. He also has a dog name "Somewhere." With the help of David's friend Harlee (Amanda Peet) and sister Liz (played by Cusack's real life sister Joan), David and Dennis begin an arduous process of learning about each other, from Dennis' incessant photo-taking habits, his inclination to eat only Lucky Charms, and his perpetual stealing, to David's continuing love of his wife, his love of baseball and his own struggles to be accepted by others. As David teaches Dennis how to be an "earthling," both earn each others' trust and eventually, they find someone who loves them unequivocally.
