Traveling to the island of Jeungdo, Korea's first no-smoking-allowed region, the cast members - all smokers - displayed telltale signs of withdrawal.

The producers suggested a challenge: whoever was caught smoking by a trained sniffing dog would have to endure the classic '1 Night 2 Days' punishment of being dunked into a frozen lake!

Kim Jun Ho was the first to be caught red-handed, with the canine sniffing out three cigarettes from the folds of his clothes. Kim Jong Min was similarly caught hiding a cigarette inside his body-warming hot pack, while Jung Joon Young was caught by the traces of cigarette smoke around his body - he had sneaked a smoke while the cameras were turned the other direction a few minutes earlier.

Don't forget to tune in to next week's episode to watch these three troublemakers get their just deserts!

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