John Burdett opens The Godfather of Kathmandu, his fourth book featuring Bangkok police detective Sonchai Jitpleecheep, with his conflicted Buddhist hero viewing the disemboweled and trepanned body of Hollywood director Frank Charles through a detached marijuana haze.

His young son is dead, his wife gone to a monastery, and he himself has been set onto a grief-shattered path of Tantric enlightenment by a smack-dealing Tibetan ex-lama in Nepal.

Sound complicated? That’s the nature of this series, whose evocative descriptions (Bangkok’s sights and smells, markets and prisons, polluted traffic) now extend to Tibetan refugees in Kathmandu. The twinned plot lines include the murder of the voraciously sexual if good-hearted director of lucrative romantic schlock, who aspired to greater cinematic heights with a film about invaded Tibet, and the $40 million heroin deal that Sonchai is brokering with Tietsin (a gray-ponytailed purveyor of esoteric knowledge) at the behest of his corrupt superior, Police Colonel Vikorn.

Both plots vanish periodically within the meandering, but readers will stay engaged as Sonchai probes the nature of karma with his half-farang (Western) wryness, while weighing in on the social complexities of Asian life, including the weirdness of the oft-married and pharmaceutically adventurous Chinese heiress Mimi Moi.

The best course is to simply give in (with Buddhist bemusement) to the total-immersion flow of Sonchai’s thought.

Burdett pegs his story with enough deceptively fleeting anchors to give it detective/thriller shape, but it is the mordant wit of his exhaustively observant “monk manqué” hero that fuels this blissful and dexterous book.

P.G. Koch reviews regularly for the Chronicle.