The Long Dark Tea-Time of the Soul relates the adventures of the holistic detective Dirk Gently, who is thrown for a loop when his client, who claimed to be being stalked by a seven-foot-tall giant wielding a scythe, is found decapitated in a locked room. While attempting to solve the mystery, Dirk has run-ins with lawyers, Norse gods, and an American woman who was present during an airport explosion. This novel examines themes of myth, power, and betrayal.
Dirk Gently, who calls himself a "holistic detective", has happened upon what he thinks is a rather comfortable situation. A wealthy man in the record industry has retained him, spinning a story about being stalked by a seven-foot-tall, green-eyed, scythe-wielding monster. Dirk pretends to understand the man's ravings involving potatoes and a contract signed in blood coming due; when in reality, Dirk is musing about what he might do if he actually receives payment for his "services"– such as getting rid of his refrigerator, which is so filthy inside that it has become the centrepiece of a show-down between himself and his cleaning woman.
The seriousness of his client's claims becomes clear when Dirk arrives several hours late for an appointment to find a swarm of police around his client's estate. The aforementioned client is found in a sealed and heavily barricaded room, his head neatly removed several feet from his body and rotating on a turn-table. While at his recently deceased client's house, he discovers that his client had a son. However, after Dirk disconnects the television set the boy had been watching, the boy promptly breaks Dirk's nose.
Nearly incapacitated by guilt, Dirk resolves to take his now-late client's wild claims seriously. During his investigation, Gently encounters exploding airport check-in counters, the gods of Norse mythology, insulting horoscopes, a sinister nursing home, a rhino-phagic eagle, an I Ching calculator (to which everything calculated above the value of 4 is apparently 'a suffusion of yellow'), a god who gives his powers to a lawyer and an advertising executive in exchange for clean linen, and an attractive American woman who gets angry when she can't get pizza delivered in London.