By William Overgard

Simon and Schuster. 352 pp. $19.45

This utterly preposterous and entirely amusing entertainment by the late William Overgard is as odd a mixture of wit and gore as one could hope -- or dread -- to encounter. Set in Singapore and Sarawak, it is the story of a middle-aged man with the strange name of Lawrence Slinng who sets out on a mission of discovery and ends up on one of survival. It's a bloody tale, yet told with such brio that in the end it is more lark than horror show.

"I'm a seaman," Slinng says. "I ship out of Port Moresby and sail a coastal charter that takes my ship, the Singapore Exile, around New Guinea and the Solomons up to Hong Kong. My base is a small place at Manu Manu. It's on the Gulf of Papua and backed up to Mount Victoria and the Owen Stanley Range -- the view is quite spectacular."

His ship is aptly named; Slinng left his home in Singapore as a young man, after a quarrel with his father, and he hasn't been back in a quarter-century. But now his father has been found dead, drowned in his bathtub, and Slinng suspects that it was not, as the authorities have determined, an accidental death. So he comes back not merely to Singapore but to Raffles, the legendary old hotel for years managed by his father:

"Once the bay was at its front door and the jungle crowded in on verandas. The last tiger in Singapore was shot under one of its pool tables and Kipling, Maugham and Coward sat in the palm court sipping stenghas and chatting up its fabulous guests. It is a place that is immediately connected with Singapore and 'Britishness,' the very symbol of the old Raj -- a monument to a vanished way of life: expected luxury, high-calorie cuisine and fawning service, by God, the one, original Raffles."

Slinng sets himself up in the old homestead and begins to prowl the streets of Singapore. Along the way he encounters, among others: Miri Brooke, a luminously beautiful young woman reputed to be "the grand-niece of old Charles, the last of the White Rajahs"; Hartog, "the Australian Onassis," a charming and unscrupulous adventurer who may or may not have played a part in Slinng's father's death; Billy Hon and various other members of the Singapore triads, gangs existing as "an extension of the old Chinese secret societies that practiced benevolent extortion and the realities of revenge."

All in all they are an unsavory crew, just what you'd expect from a novel set in a part of the world frequented by Kipling and Maugham and Coward. Each of them is out for himself and none of them is unduly fastidious about getting what she or he wants. Slinng, for example, is possessed by "this darker thing: violence," and he employs it readily: "He had learned long ago to strike first and with the intent to maim. His strength from the years at sea had made him formidable and he could be ferocious when aroused... ."

Need it be said that he is thus provoked many times in the course of "The Man From Raffles" and that his capacity for violence is always equal to the occasion? He's hardly reached Singapore before he has to do battle with a succession of foes, among them triad gangsters and officers of the law. But it's when the novel moves away from such civilization as Singapore provides and into the rain forests of Sarawak that matters really get sanguinary.

This turn of events is brought about because the Australian Onassis gets ideas about the White Raj and the possibility of linking himself up with it. It had just as well be said, though, that this turn of events is absurd and gets all the more so as the rain forest is penetrated. Center stage is taken over by the Tantu, "last of the working headhunters, the original of the Wild Men of Borneo," so cannibalism is put on the menu; Slinng is brought "face-to-face" with "the horror that lurked in the depth of man's soul," though in truth the reader is likely to find this particular version of it approximately as horrifying as the latest adventure of Indiana Jones.

But then people who enjoy Indiana Jones movies manage to do so without subjecting their plots to close scrutiny; the same strategy is recommended for readers of "The Man From Raffles." Think about it too long and you'll be utterly mystified that -- as just one case in point -- Slinng should be so in thrall to the beautiful but dizzy Miri. But there's an easy solution to this: Don't think about it.