Vijay (Amitach Bachchan) is an ex-naval officer who was court-martialled & dismissed from the navy. Vijay is now working in a coal mine. He welcomes every sign of danger & adversity in an attempt to combat the demons within him & to pay for his act of cowardliness, when as the captain of a sinking ship, he had deserted it putting into jeopardy the lives of all the passengers. Ravi (Shashi Kapoor) is an engineer, in-charge of this doomed project. Due to the negligence & the greed of its owners, the coalmine is on the verge of collapse and Ravi tries to alert the management & the workers. Ravi joins forces with the workers & Vijay in order to save the lives of his fellow workers. Mangal (Shatrughan Sinha) is a runaway convict who takes shelter from the hands of the law at this coal mine. A boisterous & egoistic man, who finally realises that there is a compassionate human being within him, also ends up joining the quest for justice. Kaala Patthar is a film about how different people from different walks of life & backgrounds come together and show there character to fight the forces of nature in what seems like a losing battle.