A great cast is hung out to dry in this low-energy quirk-comedy that seems to exist solely for its desert climes and unrealized premise. Steve Buscemi is the eponymous John; why he’s canonized in the title isn’t clear — neither is much else — though the fact that John’s last name is Alighieri heralds the fact that writer-director Hue Rhodes based his debut feature on Dante’s Inferno.

John is a recovering gambling addict working in insurance in Albuquerque. Egged on by the office strumpet, Jill (Sarah Silverman,  great but overused), he approaches his firebrand boss (Peter Dinklage, great but underused) for a raise and is instead paired with the company’s top fraud investigator, Virgil (Romany Malco, great but underused, despite being in almost every scene) and put to the test with a tricky assignment on the outer circle of his own version of hell: Las Vegas. After John and Jill consummate their bond off-screen in the first of many needless plot points, John sets off with Virgil on some business about a demo’d 1970 Ford Falcon and a stripper in a wheelchair.

An unusual lap dance, John Cho in a fireproof suit, Tim Blake Nelson as a naked survivalist and lots of instant lotto tickets are aimless set-ups that go nowhere from there. Understatement is a dandy approach, sure, but the yawning dearth of payoffs in this high-stakes comedy suggests something closer to unfinished business. Saint John’s title notwithstanding, there’s nothing divine, let alone comedic, about it.