The Buddenbrook family gathers to celebrate the baptism of Thomas’s firstborn son, Johann. As the family prepares hot chocolate, cake, and decorations, distinguished guests, including the mayor, arrive. The arrival of Johann (nicknamed Hanno), named after his grandfather, brings hope for the continuation of the Buddenbrook family legacy.

Christian visits Thomas late in the evening to discuss his dire situation. He confesses that his business in Hamburg is failing, and he is in debt. Despite receiving a significant sum from Thomas previously, Christian has not managed to turn his fortunes around. He also reveals his relationship with the actress Aline Puvogel, including that her third child is his. Christian proposes closing his business and moving to London, asking for financial support from the family. Thomas agrees, albeit reluctantly.

Senator James Möllendorpf, a diabetic, dies due to an excessive indulgence in sweets. The city discusses who will succeed him in the senate. The Buddenbrook family, particularly Tony, hopes for Thomas to fill the vacancy. Amid various candidates, Thomas and Hermann Hagenström emerge as leading contenders.