Amar Deep tells the story of Raja, a young man who was adopted by a powerful criminal don named Ashok Kumar. Following the don's death, Raja inherits his vast property and wealth, deciding to distance himself from the criminal activities that once defined his adoptive family. However, the immense power and affluence quickly change Raja, filling him with arrogance and entitlement.
Raja's attention turns to Radha, the daughter of his loyal servant Ramu. He requests Ramu's permission to marry her, and surprisingly, Ramu agrees. Yet, Radha herself refuses Raja's proposal, revealing her love for Kishan, a man from her community. Raja soon discovers their secret meetings and confronts Ramu, who forbids Radha from seeing Kishan. Intent on controlling the situation, Raja uncovers a secret from Kishan's past, uses this knowledge to his advantage, and surprisingly arranges a grand wedding between Kishan and Radha.
Though Raja appears magnanimous, providing Kishan with a lavish marriage and entrusting him with significant responsibilities requiring frequent travel, Kishan grows suspicious. He begins to wonder if Raja's kindness is a plot to keep him away so that Raja can be close to Radha himself. The story unfolds with Kishan unraveling the true motives behind Raja's seemingly generous acts, leading to intense drama and unexpected revelations.