Shanmugam, known as Benz, is a middle-class taxi driver who treasures his black Ambassador car, treating it almost like a family member. He leads a content life with his wife Lalitha, son Pavan, and daughter. One day, when his car meets with an accident, the mechanic misuses it for illegal activities. In a desperate bid to reclaim his only source of livelihood, Benz approaches SI Benny. However, CI George Mathen intervenes, setting off a chain of strange events. Benz is then asked to drive the officers to a wedding and later to a deserted forest area, where a shocking revelation awaits. What exactly happened, and are the officers involved in something more sinister? Thudarum unfolds the answers.