Fourth season.
Discs are in excellent condition
Physicists Leonard and Sheldon understand everything from the inescapable gravitational pull of a black hole to the intricate structure of the atom. But take those atoms and assemble them into a woman, and their comprehension comes to a grinding halt. And when Penny, a woman with all those atoms in all the right places, moves in across the hall, Leonard and Sheldons universe begins to expand in ways they never could have imagined. When series creators Chuck Lorre (Two and a Half Men) and Bill Prady (Dharma & Greg) combine equal parts science, superheroes and sex and add stars Johnny Galecki (Roseanne) and Jim Parsons (Judging Amy), the result is an explosively funny comedy for the nerd in all of us.