The Vampire Diaries Season 2 Episode 6 (The Vampire Diaries s02e06) with title “Plan B” aired on Thursday, October 21st 2010 at 08:00 pm via CW Network.
Here is summary for The Vampire Diaries Season 2 Episode 6 :

Despite Elena’s efforts to keep Jeremy safe, he offers to help Damon and Alaric deal with Katherine. Sheriff Forbes and Caroline share a few rare moments of quality mother/daughter time. Bonnie accidentally discovers new information about Mason and shares it with Stefan, leading Damon to take matters into his own hands.