Penny secretly enrolls in a history class at community college. When Leonard finds her paper on slavery, he rewrites it against her wishes, leading to a conflict about his lack of faith in her abilities.
Fans often debate Leonard's behavior in this episode, specifically his decision to rewrite Penny's paper behind her back. [S6E6] The Extract Obliteration
"The Big Bang Theory" The Extract Obliteration (TV ... - IMDb Penny secretly enrolls in a history class at