The decidedly lowbrow dramas — with names like “Bad Housewife” and “Red Bean Bread” — have, in fact, become something of a cultural Trojan horse, sneaking visions of the bustling South into the tightly controlled, impoverished North alongside the usual sudsy fare of betrayals, bouts of ill-timed amnesia and, at least once, a love affair with an alien.

North Korea’s leader, Kim Jong-un, has issued increasingly pointed warnings to his subjects about the “poisonous elements of capitalism” crossing China’s border with the North, tempting even his Communist elite. Defectors say there has been a severe crackdown on smugglers, and in the fall, South Korean intelligence reported hearing that Mr. Kim was so shaken by the spread of the soaps that he ordered the execution of 10 Workers’ Party officials accused of succumbing to the shows’ allure, according to lawmakers who had been briefed on the matter at a parliamentary hearing.

Few people outside North Korea think the TV adventures of the lust-driven and lovelorn could lead to the overthrow of the Kim family dynasty, which has survived for decades despite international isolation and sanctions. But the infiltration of the dramas into even elite circles, despite the threat of prison or worse, is a potent indication of the challenges Mr. Kim faces in a globalized world. (The swift arrival in the North of at least some bootleg copies of “The Interview,” the comedy that North Korea viewed as an “act of war,” is another.)

Since he came to power in 2011, Mr. Kim has struggled to open the North just enough to keep his top loyalists happy, plying them with imported goods, while maintaining control in a country where government-installed intercoms in every home still blare reminders of required ideological education classes. He allowed an estimated two million people, close to 10 percent of the population, to own cellphones, but ensured they could not call abroad. And, despite a crackdown, the country has seemed unwilling, or unable, to fully dismantle the smuggling networks that bring in not only banned soap operas, movies and K-pop videos, but also much-needed trade.

Defectors say the soaps have had an outsize impact, less for their often outlandish plots than their portrayals of the creature comforts of South Korea — a direct contradiction to decades of indoctrination about the inferiority of the South, and capitalism. It was those portraits of wealth, Jeon Hyo-jin said, that inspired her to make the dangerous decision to flee in 2013 at the age of 18.