Phoebe Tonkin will stop by tomorrow night's episode of The Vampire Diaries, debuting as a werewolf named Hayley on "The Rager."

But what can fans look forward to when the calendar flips to November and the television world encounters Sweeps, that all-important period where advertisers buy space and networks look to impress them?

The CW has released the following episode descriptions for upcoming installments, with storylines that include a costume party; a flashWAYback and a dangerous mistake...

November 1 ("The Five"): At a fraternity costume party, Damon takes advantage of the wild scene to give Elena a lesson in choosing a victim. Meanwhile, Klaus tells Stefan about an encounter with a powerful group of vampire hunters - led by Paul Telfer as Alexander, above - in the 12th century.

November 8 ("The Killer"): When Connor takes Jeremy, Matt and April hostage at the Grill, Stefan and Damon have a serious disagreement about the best course of action, and Elena again caught between the two brothers.

November 15 ("We All Go A Little Mad Sometimes"): Terrifying hallucinations leave Elena shaken and confused, causing her to make a dangerous mistake.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.