Former auxiliary firefighter Ahn Jung-won now works in equipment storage at his local fire station, quietly sorting supplies while carrying unspoken memories of the past. When his former junior from military service, Kang Yi-jun, is assigned to the same station as a full firefighter, the two confront unresolved events from their years of duty. As emergency calls, past accidents, and survivor guilt resurface, the musical moves between past and present, exploring wounds that never fully healed. The narrative emphasizes the quiet persistence of those who continue to serve despite invisible scars.