Episode 3 of the "Mysteries of Paris" series explores the story of Nicolas Flamel and his connection to alchemy. Flamel was a 14th-century Parisian who became famous for supposedly discovering the secret to the philosopher's stone, a mythical substance said to have the power to transform base metals into gold. The episode delves into the history of alchemy and its association with Flamel, examining the clues and legends surrounding his life and the quest for eternal life through alchemical means. The video offers an intriguing look into the mysteries surrounding Flamel's legacy and his impact on the city of Paris.