In the final days of the Korean War, a fragile ceasefire is declared, but battles still rage over the ownership of a small hill that holds strategic importance. An army intelligence officer, Kang Eun-pyo, is dispatched to the Eastern front to investigate the suspicious death of a company commander. Upon arrival, he encounters old friend Kim Soo-hyeok, who has become an enigmatic and hardened leader of the unit, known for its high casualty rates and unrelenting dedication to holding the hill. As Eun-pyo navigates through the chaos and attempts to uncover the truth behind the death, he witnesses the brutal reality of war and the fluctuating loyalty among soldiers.

Amidst this uncertainty, there is also an uneasy exchange of goods between opposing sides at night, revealing a complex humanity behind enemy lines. As battles intensify, loyalty and morality are continuously tested, and Eun-pyo discovers that the true enemy may not be as clear-cut as he originally believed. The soldiers on both sides are trapped in a desperate fight not just for territory, but for survival and sanity in the face of overwhelming odds. Their personal stories and moral dilemmas unfold against the backdrop of a war with no clear end in sight, forcing them all to question what they are really fighting for.