The story is set in the poverty-stricken Victorian London, where an elderly couple share a miserable life. The only source of joy for the couple is a chip glass ruby that the old man received from his fiance before she died. One Christmas, the woman asks the old man to sell the ruby so they could have money and enjoy the holiday. The old man sells the ruby with a heavy heart and then goes to a shop where the ruby is displayed, reflecting the sad irony of his life.
The story explores themes of love, sacrifice, and the bittersweet nature of life. The old man's decision to sell the ruby is a sacrifice he makes for his wife's happiness. He knows that she deserves a better life and he is willing to give up his only source of joy for her sake. The story also highlights the power of love, as it is the couple's love for each other that sustains them through their difficult circumstances.