After being freed from his life in an underground bunker, a man sets out to make a movie of the only TV show he has ever known.

Brigsby Bear Adventures is a children's TV show produced for an audience of one: James. When the show abruptly ends, James's life changes forever, and he sets out to finish the story himself.—Brigsby Bear Productions

Superfan James (Mooney) is obsessed with the clever if quaintly goofy kids' show Brigsby Bear to the point of religiosity. A bright, sensitive young adult still living at home, he has grown up with this fantasy series, and the program has grown with him as well - getting more complex over the years. But when the show abruptly ends, James's life changes forever, and he sets out to finish the story himself.