Seventeen years ago, three good friends went up the mountain, but unexpectedly encountered an accident and were trapped in the snow mountain. Fortunately, they were eventually rescued. Since then, the three have become life-and-death friends, and their bond has deepened over the years. Tai Hyun (played by Ji Sung) is a diligent and justice-oriented firefighter living a modest yet harmonious life with his wife and daughter; Jin Cheol (played by Ju Ji Hoon) works at an insurance company and is clever and resourceful, often resorting to cunning means; Min Soo (played by Lee Kwang Soo) is the one struggling the most among the three, running his small business and usually relying on his two good friends. To defraud the insurance company for a large sum of money, Jin Cheol collaborated with Tai Hyun’s mother to plan a robbery and arson case. The typically timid Min Soo was persuaded by Jin Cheol to participate in this case. However, things did not go as planned, and tragedies ensued one after another. The three friends found themselves trapped at the center of this tragic whirlpool.