Dirk Gently has followed the sinister advertising executives Simon and Cynthia Draycott through a dimensional portal which divides St Pancras International Railway Station in our world with the Feasting Hall of Valhalla - its shadowy opposite in the world of the Norse Gods, a race of superbeings who have ceased to be particularly super and now live mostly alongside us as vagrants and destitutes. Only very rarely do they gather in Valhalla and this time the occasion is the grand and thrilling Challenging Hour - promising an epic battle between Odin, father of all the gods, and his son Thor, God Of Thunder, angered at the old man's folly.

Odin has been persuaded by the unsavoury goblin Toe Rag to trade his immortality to the Draycotts for the comforts of a warm bed and 24-hour nursing care. Thor wants to tear up the contract - but must find it first. While he and the American journalist Kate Schechter travel by hammer through the skies over Asgaard to consult the charming if suicidal Tsuliwaensis as to how best to proceed in their attempt, Dirk must somehow stop the Draycotts from exercising the hidden clause in the agreement that will give them godlike powers forever - and be reunited with his former secretary Janice Pearce - who has been placed under a curse that has turned her into a vending machine with many cans of fizzy drinks stuffed into the most uncomfortable places.

The result involves Thor losing his temper and getting it back again, the mysterious eagle that has plagued everybody finally being restored to its proper form, Elena the Cleaner proving to be much more influential in Asgaard than she ever was behind a dishcloth, Dirk having an uncomfortable encounter with a motorcycle ... and a kitten.