It's approaching Christmas, and Leonard's mother is coming for a visit, something Leonard fails to tell Penny. Sheldon surmises it's because Beverly Hofstadter will not approve of Penny as a suitable mate for her son. Leonard has not even yet told Beverly that Penny is his girlfriend. Conversely, when Beverly arrives, Leonard finds out that Sheldon knows more about what's going on in her life than he does. When Leonard does find out news about the senior Hofstadter household, he becomes emotionally distraught as what he deems important news to him was previously withheld. But more importantly, Leonard sees this action as a further demonstration of the poor relationship he has with his family. Meanwhile, Penny believes she has a way for Beverly to be a bit more emotionally expressive.