Samson, imprisoned and blinded by Philistines in Gaza, laments his state, noting that the person who was supposed to save Israel from the Philistines has now become their slave. He explains that his blindness is by far the hardest aspect of his imprisonment, as he feels cut off from God's creation. He feels so demoralized that he even describes himself as a living grave. His speech is interrupted when he hears footsteps coming his way.
The chorus appears and they, too, lament Samson's fall. They express their sorrow over how the man who once slew a lion with his bare hands now sits imprisoned in rags. They also note the tragedy of Samson's blindness, but encourage Samson not to blame God for what has happened to him. Samson admits that he himself is the only one to blame, as he was the one who told Delila the Nazirite secret about his hair. The chorus announces that someone is coming, and Samson's father Manoa appears.
At first, Manoa does not recognize Samson. He wants to blame God for punishing Samson too harshly, but Samson tells his father the fault is only his. His father reveals that the Philistines plan to have a big celebration on this day to honor their god, Dagon, and that Samson will be paraded in front of them as evidence that Dagon is the true lord. Manoa plans to entreat the Philistine lords with ransom money to free Samson, but Samson refuses, saying he will be useless to Israel as a blind and idle man. Manoa leaves, and soon after, Samson's wife Delila appears.
Delila confesses her guilt and seeks forgiveness from Samson for what she did. Samson refuses to believe her, thinking that she is only a manipulative woman, incapable of feeling love or remorse. She tells Samson that she loved him so much, she saw his imprisonment as a way to keep him safely hers forever, and that she did not know the Philistines had planned to harm him. She then tells him that she betrayed him for her country and religion, being influenced by the Philistines in power. She once again asks for his forgiveness and promises to ask the government to let her take him home, but Samson once more refuses, and Delila leaves.
Next, a giant named Harapha appears. He mocks Samson and reveals that he wished to fight with him when he was in his best shape. Samson assures Harapha he could win a fight against him even now, blind and unarmored, and their combat would prove whose god was the true God. Harapha refuses to fight Samson, and Samson mocks him until Harapha leaves.
Next, an officer comes and tells Samson that he has to attend the public celebration in the honor of Dagon. At first, Samson refuses, thinking that to do so would offend God. However, he soon feels a change within himself and agrees to go with the messenger.
Manoa returns just in time to hear what Samson has done: he killed every Philistine, and himself, by destroying two large pillars and collapsing the entire structure of the theatre where the celebration was held. Manoa and the chorus lament Samson's death but celebrate his heroism and commitment to God.
