The Vampire Diaries Season 2 Episode 7 (The Vampire Diaries s02e07) with title “Masquerade” aired on Thursday, October 28th 2010 at 08:00 pm via CW Network.
Here is summary for The Vampire Diaries Season 2 Episode 7 :

Stefan and Damon decide on a new plan to deal with Katherine at the Lockwood’s masquerade ball. Katherine calls on an old friend, Lucy, to attend the ball with her. Bonnie, Jeremy and Alaric all do what they can to help Stefan and Damon