Dirk Gently (of Dirk Gently's Holistic Detective Agency) becomes embroiled in a big imbroglio after arriving holistically late for a detective appointment with a record industry man who wanted protection from an alleged monster with a scythe that was allegedly stalking him because of a blood contract. Or something. Dirk took his claim lightly and wasn't listening too hard, which backfires when he stumbles upon a crime scene centered around the decapitated record industry man. He was found in a sealed room, head spinning on a turntable, and nobody can figure out how the hell he died without the killer remaining in the room with him. The resulting guilty conscience gives Dirk just the push he needs to take his job seriously, and he sets out to detective his way into a goddamn answer!
Airport counters explode, train stations turn into godly meeting places, calculators give wildly unhelpful answers ("a suffusion of yellow"), Thor, Norse god of thunder and my college-era wooden penis, throws temper tantrums, a professional couple makes contracts on Odin's behalf, an eagle that is not really an eagle throws a temper tantrum in Dirk's apartment, and a filthy, filthy fridge saves the day.
Similar to Gaiman's American Gods, gods have been created because of people's belief in them, but when people stop believing, they don't vanish, they just sort of hang out, and mostly get poor. No resume and no easily described skills* = no job prospects. Gods were not designed for the modern world, alas.
If you loved Adams' Hitchhiker's, you will probably like this book. If you only liked the superior series, you're not missing much by skipping this one. I haven't read any other Dirk Gently novels, but I also don't have much desire to do so. It was funnier in concept than in execution.
*I fly on a hammer!