The Big Bang Theory: Season Six Episode Fifteen: "The Spoiler Alert Segmentation"
Leonard gets into a fight with Sheldon after latter gives away the ending of Harry Potter book that Leonard is reading. He decides to move in with Penny, a decision which Penny clearly is uneasy with, although she has no reason to say no to the arrangement. Similar situation arises for Sheldon when Amy proposes to becoming his roommate after she learns about the fight. Meanwhile, Howard and Bernadette take off to a conference in Las Vegas, after asking Raj to check on Mrs. Wolowitz.
Penny and Sheldon confess to each other their discomfort over the situation. They decide to tell the truth to their respective partners. However, Sheldon gets scared and lies to Amy that Leonard may come back since Penny doesn't want to live with him. This causes a brief spat between the quartet. Amy gets angry and tells that she will get even with the boys by moving in with Penny, a suggestion that makes Penny uncomfortable again. Leonard, looking dejected, returns to Sheldon, but not before Sheldon spoils a major plot-point from The Walking Dead.
Meanwhile, Mrs. Wolowitz pampers Raj, who decides to stay for the night on seeing that she is lonely and depressed. When Howard learns about this, he tells Raj that his mother is using food and guilt to prevent him from leaving. Soon Raj comes to same conclusion and tries to escape from a window, but Mrs. Wolowitz pulls him back.