Sheldon's latest scientific breakthrough makes him feel like a fraud – and threatens to haunt him forever. Meanwhile, Howard's romantic gesture to Bernadette causes Penny to step up her game with Leonard.
Tool Time continues to be a "jewel" despite the continued excess presence of the Binford name. Things rapidly turn sad when Al decides to take his mother out to dinner to tell her he's going to get married... and she has a heart attack and dies.
When Kat winds up getting sick just days before her favorite local TV newsman plans a visit to the café, she turns in to her alter ego, Katzilla. Meanwhile, after Randi lands her dream apartment, Max starts trying to find his own.
Blossom and a friend plot to spy on a woman from Nick's past.
