If you haven't read Harry Potter (and are planning to) then keep your ears shut around Sheldon. Leonard's just discovered JK Rowling's magical world, and when his roommate starts getting loose lipped about the plot, he ups sticks and moves in with Penny. Unfortunately for Sheldon, Amy sees this as he cue to bunk up with him, and moves in before he can even look for anyone else. Meanwhile Howard and Bernadette head off on a road trip, leaving Raj to take care of Mrs Wollowitz....