The complete fourth season of the US comedy series revolving around a pair of socially dysfunctional university physicists. Leonard (Johnny Galecki) and Sheldon (Jim Parsons) seem content enough working at physics during the day and playing computer games and hanging out with their fellow scientists and social recluses, Howard Wolowitz (Simon Helberg) and Rajesh Koothrappali (Kunal Nayyar), at night. That is, until beautiful, free-spirited Penny (Kaley Cuoco) moves into the apartment next door and opens up the possibility of a whole new world of love. Episodes are: 'The Robotic Manipulation', 'The Cruciferous Vegetable Amplification', 'The Zazzy Substitution', 'The Hot Troll Deviation', 'The Desperation Emanation', 'The Irish Pub Formulation', 'The Apology Insufficiency', 'The 21-Second Excitation', 'The Boyfriend Complexity', 'The Alien Parasite Hypothesis', 'The Justice League Recombination', 'The Bus Pants Utilization', 'The Love Car Displacement', 'The Thespian Catalyst', 'The Benefactor Factor', 'The Cohabitation Formulation', 'The Toast Derivation', 'The Prestidigitation Approximation', 'The Zarnecki Incursion', 'The Herb Garden Germination', 'The Agreement Dissection', 'The Wildebeest Implementation', 'The Engagement Reaction' and 'The Roommate Transmogrification'.