Man Underground is an alien conspiracy film done in a somewhat mumblecore style. Willem is a heavily disheveled and socially awkward man, who adamantly believes that he encountered aliens while working as a geologist. Wanting the truth to get out, Willem agrees to Todd's suggestion to make a movie about his experiences, since "fiction can make facts more digestible." However, Willem soon begins to believe that he is in danger, which results in a growing sense a paranoia.
Man Underground is a film that purposely keeps it ambiguous whether Willem is a delusional crackpot or if there is some level of truth to his alien conspiracies. Man Underground is much more a character film, with the bulk of the story focusing on the three leads of Willem, Todd, and Flossie. Flossie is the true outsider of the trio, who starts off being fascinated by Willem, but starts to become a bit freaked out at the level of his paranoia. Altogether, Man Underground is a fine low key alien conspiracy film.