Collection of three episodes from the US sitcom set at Christmas time. The series revolves around two university physicists, Leonard (Johnny Galecki) and Sheldon (Jim Parsons), their beautiful, free-spirited neighbour, Penny (Kaley Cuoco), and their friends, Howard Wolowitz (Simon Helberg) and Rajesh Koothrappali (Kunal Nayyar). In 'The Bath Item Gift Hypothesis', from Season Two, Sheldon struggles to decide what to give Penny for Christmas. In 'The Maternal Congruence', from Season Three, Leonard's mother Beverly (Christine Baranski) comes to visit, much to his horror. In 'The Santa Simulation', from Season Six, a game of 'Dungeons and Dragons' reminds Sheldon why he dislikes Christmas.