[4][5] The film is an unorthodox slant on holiday traditions that follows a jaded, gritty Santa Claus who struggles with ennui, production issues, government interference, and an embittered assassin sent by a vengeful naughty kid.

Chris Cringle and his wife Ruth operate a Christmas present workshop on an old isolated farm near the small town of North Peak, Alaska.

Struggling with declining revenue over the years due to children becoming increasingly vicious, the United States Government, who maintains an interest share in Chris's business because Christmas is a major economic stimulus, starts cutting back on their subsidies.

To remedy Chris' income loss, US military Captain Jacobs is sent to propose a two-month contract for producing jet fighter components, which is outright refused.

Billy Wenan, an immoral and pernicious boy who lives with his ailing old money grandmother, is the quintessential vicious child who commits several despicable acts against people he considers inferior (i.e. threatening a girl who won first place in a science fair).

Backtracking Miller's assignment, Chris and Ruth pay a visit to Billy and interrupt him spiking his grandmother’s milk with fentanyl to cover his check forgeries.

The website's critics consensus reads, "Fatman takes a surprisingly serious approach to a potentially ludicrous twist on the Santa Claus legend, aiming for edgy but mostly missing the mark.

"[25] Julian Roman of MovieWeb also gave the film a positive review and wrote, "Fatman reflects the worst instincts of modern times.

[29] Owen Gleiberman of Variety gave the film a negative review and wrote, "Yet you get the distinct feeling that the Nelms brothers think this is all a lot funnier, crazier, and more resonant than it is.