During the Nazi occupation of Poland, a sewer worker named Leopold Socha discovers a group of Jews attempting to escape the liquidation of the Lwów Ghetto by hiding in the city's extensive sewer system. Initially motivated by the promise of financial reward, Socha agrees to protect and sustain the group, which includes men, women, and children, led by a man named Mundek. As they struggle to survive the harrowing conditions underground, Socha faces moral dilemmas and growing personal risks, both from the Nazis and from his neighbors, who begin to suspect his activities.

Tensions rise as the months drag on, with dwindling supplies and the constant threat of discovery pressuring everyone involved. The confined environment of the sewers amplifies the group's internal conflicts, yet also forges unexpected bonds. Socha's initial motivations gradually shift, revealing the complexity of human compassion in the face of extreme adversity. As trust develops between him and the hidden Jews, they all have to confront their fears and prejudices, redefining their concepts of loyalty and heroism. The story poignantly explores themes of survival, sacrifice, and the transformative power of empathy in the darkest of times.