"A Tale of Two Cities" is set in London and Paris before and during the French Revolution. The novel begins in 1775 with Jarvis Lorry, a banker at Tellson's Bank, traveling to Paris to reunite Lucie Manette with her long-imprisoned father, Dr. Alexandre Manette. Dr. Manette has been released after spending eighteen years in the Bastille, where he was unjustly imprisoned due to the cruelty of the French aristocracy. He is found in a fragile state, obsessively working as a shoemaker, but Lucie's love and care help him regain his sanity.

Meanwhile, Charles Darnay, a French aristocrat who renounces his title due to his disdain for the oppressive rule of his family, moves to England. He falls in love with Lucie Manette and eventually marries her. In England, he is falsely accused of treason but is acquitted with the help of his lawyer, Sydney Carton. Carton, though brilliant, is a self-loathing alcoholic who recognizes in Darnay the man he could have been. Despite his feelings of worthlessness, Carton secretly loves Lucie and vows to do anything for her happiness.

As the French Revolution ignites in 1789, the narrative shifts to the chaos in Paris. The revolutionaries, led by the ruthless and vengeful Madame Defarge, seek revenge against the aristocracy. Darnay, unaware of the danger, returns to Paris to help a former servant. However, he is arrested and sentenced to death due to his noble lineage. Dr. Manette, once a victim of the aristocracy, attempts to save him, but the revolutionaries, including Madame Defarge, are relentless.

Sydney Carton, recognizing an opportunity for redemption, devises a daring plan. He takes advantage of his physical resemblance to Darnay, sneaks into the prison, and swaps places with him. Darnay escapes with his family while Carton, fulfilling his promise to Lucie, sacrifices himself. As he faces execution by guillotine, he reflects on his life and finds solace in his sacrifice, believing that he has finally found meaning. His last words, "It is a far, far better thing that I do, than I have ever done..." become one of the most famous lines in literary history.

The novel concludes with the triumph of love and sacrifice over hatred and vengeance. Dickens masterfully intertwines personal and historical struggles, portraying the horrors of the revolution while highlighting the resilience of the human spirit. "A Tale of Two Cities" remains a timeless tale of redemption, transformation, and the enduring power of love.