Leonard and sheldon are brilliant physicists geniuses in the laboratory, but socially challenged everywhere else'. '.strtoupper('e')nter their beautiful, street smart neighbor, penny, who aims to teach them a thing or two about life'. '.strtoupper('d')espite their on again, off again relationship in the past, leonard believes he's found true love with penny and they have finally gotten engaged'. '.strtoupper('e')ven sheldon has found a female companion, entering into a relationship agreement with neurobiologist amy farrah fowler'. '.strtoupper('i')n their free time, leonard and sheldon continue to enjoy frequent trips to the comic book store and fantasy role playing games with their ever expanding universe of friends, including fellow scientists koothrappali, wolowitz and wolowitz's adorable microbiologist wife, bernadette.