Leonard, Sheldon, and Wolowitz run into problems when they file for a patent for their infinite persistence gyroscope.
The CBI team investigates when the body of a female army medic who worked with soldiers suffering from PTSD is found near a military base.
The son of devout Jehovah's Witnesses is accused of killing his teacher after being caught fleeing the scene of her murder; the Democratic National Committee hires the team to investigate a second case.
Christy's patience is tested by everyone she knows; while Bonnie runs into an old rival.
Eric plans a romantic weekend alone with Sloan; Turtle and Drama find a pair of dream dates at the dog park.