When the Mona Lisa develops a toothache, she struggles to smile for Leonardo Da Vinci’s famous painting. Peabody and Sherman step in to help, trying various remedies to ease her discomfort and restore her iconic smile. As they navigate the quirks of dental care in the Renaissance, the episode humorously explores the challenges of artistry and the importance of capturing the perfect expression, all while showcasing Peabody's clever solutions to historical dilemmas.