Stiles is targeted by his nursery school classmate to lose her virginity on her 17th birthday.

Only Stiles virginity key would be stolen out from under his nose before the deed.

Derek and Isaac bring Peter in for his help.

The bruises on Allison's and Lydia's arms are the logo for the bank where Eric and Boyd are being held.

Allison goes to the bank alone when she takes Derek's words about not having enough evidence to heart.

Erica is dead.

Decaulion has kept Boyd and the other caged werewolf, Cora, starved of moonlight so they would be particularly powerful. 

Derek's younger sister, Cora, is the other captive.

Derek forces Scott's hand in telling Allison about her mother after she sets Boyd and Cora free.