The drugs came in by air from Bombay. The stolen cars and the South African rand came by road from Johannesburg. The swap was made here in this upcountry capital of a landlocked, hard-luck nation where most people have spent the past decade getting poorer. It was a sweet piece of business while it lasted.

Indian drug makers got cash for sleeping tablets they could not sell legally at home. White South African yuppies got pills that made them crazy when crushed and mixed with their liquor. And Zambian traders got rich, filthy rich by Zambian standards.

Affluence, in fact, is what finally did them in. In a country that can't afford bread, the smugglers' BMWs and wads of money attracted too much attention.

"How can Zambians who have no business in South Africa have so much money?" asked President Kenneth Kaunda, after personally ordering the arrest of 10 drug smugglers. Kaunda said they would stay in prison until police found out "how they got these big cars when we [Zambia] have no foreign exchange."

That was last spring. More than 30 accused drug smugglers -- some of them among the best known political figures in Zambia -- are now locked up by presidential decree, and the particulars on the biggest scandal in Zambian history are just starting to dribble out of the courts.

Here in the capital, the scandal has lost none of its deliciousness. Bankers and diplomats eagerly turn to it at cocktail time after desultory discussions of Zambia's unpayable foreign debt. What whets everyone's curiosity is that almost no one is above suspicion. Higher-ups in Zambian society are still being locked up by the president. The Times of Zambia has editorialized: "One only needs to disappear from his usual club for a day or two before he qualifies as a detainee."

Among the accused are two Zambian diplomats, an assistant controller of customs, several prominent Lusaka businessmen, and a handful of South Africans who allegedly used to drive between Johannesburg and Lusaka, via Botswana, in specially designed false-bottomed cars.

The leading figure of the Zambian Connection is one of the nation's founding fathers -- Sikota Wina, 54, a crusader for Zambia's independence in the early 1960s, a government minister for 17 years, a former member of the Central Committee of the president's ruling party. When he was nabbed in a New Delhi airport, with 100,000 pills in his suitcases, he listed his occupation on the arrest report as "freedom fighter."

Wina's wife, the Princess Nakatindi (great-granddaughter of King Lewanika, one-time boss of Barotseland in what is now western Zambia), is also in prison on drug-smuggling charges. She recently sued the government to recover 429,000 rand, worth nearly half a million dollars when it was seized in 1983. Police confiscated the South African currency, which they say is drug loot, from a car driven by the princess' brother.

Finally, and most mysteriously, the president late last month ordered the arrest of Vernon J. Mwaanga, 41, a former foreign minister, successful fruit exporter and one of the most influential black businessmen in southern Africa.

The president and Mwaanga are longtime friends. When Mwaanga was just 20 years old, the president named him to the first of a succession of key diplomatic and ministerial posts. For years, Mwaanga personally brought Kaunda baskets of fresh fruit.

Under Zambian law, the government does not have to say publicly why Mwaanga is in jail. Mwaanga himself was entitled to be told of the charges against him only last week. Whispered speculation runs riot in Lusaka, but all that can be said with certainty is that Mwaanga was imprisoned under the same Preservation of Public Security regulations that Kaunda has invoked in arresting accused drug smugglers.

Neither drugs nor smuggling is new in Zambia. For centuries, farmers and herders have lightened their load by smoking dagga, a hallucinogenic African marijuana. Smuggling, too, is a national pastime. On the Zambia-Zaire border, Army brigades are routinely dispatched to disperse the hordes who creep through jungles pushing wheelbarrows full of contraband soap, cooking oil and cornmeal.

The pills-for-cars, pills-for-cash scam, however, apparently began only about five years ago. It quickly proved to be the fastest way ever devised to make hard currency in this country where per capita income is $580 a year and falling.

The pills are known by their brand name, Mandrax. They are powerful sleeping pills derived from the mandrake plant, a poisonous nightshade, and are produced in Bombay. Although sale of Mandrax pills within India is strictly regulated, they can be obtained easily and at bargain prices by foreigners.

In the Zambian Connection, Mandrax was purchased in Bombay for about $4 per 1,000-pill box. By the time one pill got to South Africa, where young whites like to crush it and either smoke it with marijuana or mix it with drinks (producing what one South African journalist describes as a "strong, mean and ugly high,") it sold for about $2.50.

The potential profit on 100,000 tablets, which cost about $400 in Bombay and fit nicely into two suitcases, amounted to nearly $250,000.

Those familiar with Lusaka's Mandrax business say South African traders, who came north with stolen cars, were willing to swap a $20,000 BMW sedan for five or six boxes of Mandrax, worth $20 to $24 in Bombay.

Wina is charged with having traded 20 boxes of Mandrax (worth $80) for a Mercedes-Benz. With profits like these, it was not long before the twice weekly flights from India to Lusaka were filled with Zambians with large suitcases.

Nor was it long before customs officials at the airport were, according to government prosecutors, taking large bribes not to open those suitcases. Nor was it long before confiscated suitcases full of Mandrax, after having been locked away in government customs warehouses, were discovered missing. Sometimes suitcases went into the warehouses full of Mandrax, but by the time police checked their contents they were full of aspirin or rice.

Quite suddenly, in Lusaka's two five-star hotels and at the glittery Moon City disco on Cairo Road, there appeared a new breed of Zambian swinger.

"You would see people flaunting dollar or pound notes," noted the Times of Zambia. "It was not uncommon for a person to enter a hotel and boast about his latest car model from South Africa, and talking publicly about 'beating' customs men by bringing in suitcases of Mandrax undetected as free as crossing Cairo Road."

The money-bags braggadocio of drug traders, many people here believe, finally forced Kaunda to call in a team of special investigators.

Still, they had practically no power to hold suspects. Zambia's smuggling laws were written for cornmeal smugglers, and the maximum penalty for a Mandrax trafficker was a $25 fine.

So Kaunda invoked a draconian security act, intended to head off coups, and the arrests began. Diplomats here say Zambian investigators worked with police in Bonn, London, Pretoria and Washington to arrest 32 suspects in Zambia and 26 others abroad. Kaunda waived diplomatic immunity for one diplomat arrested in London.

The braggadocio, however, of at least one alleged Mandrax trader was not shaken simply because he got caught by police.

Wina used the occasion of his arrest and five-month detention in India to attempt a political comeback in Zambia. He had left politics in the late 1970s.

According to government prosecutors, Wina jumped bail in New Delhi in late 1984 and forged a Sudanese passport. Then, under the name Hussein, he flew home to Lusaka to a gala reception thrown by his family.

At the reception, where family members wept with joy, beat drums and ululated, Wina told reporters that his New Delhi airport arrest had been a misunderstanding.

"In India, they plant luggage on every traveling VIP. This is what happened to me. I was persecuted on no grounds whatsoever," he said.

"I am coming back into politics," Wina declared. "I fought for the independence of this country. I think it is better to thank people who helped to bring about the fruits which people are now enjoying."

Four months later, in April of this year, Wina was jailed, along with Nakatindi. Their trial is still pending.

Flashy, free-spending Zambians are in short supply these days at the Moon City disco, bartenders say. As before the Mandrax era, most of the shiny cars in Lusaka are again owned by Zambians with connections not to drugs, but to the government.