Part A
Jackson has moved to London. A new teacher, Jennifer Blake, has joined Beacon Hills High school with a keen eye for Derek. While infiltrating the Alpha Pack who have taken refuge in a bank, they discover that Erica is dead and Derek's sister Cora is a prisoner and free them.
Scott, Allison, Sam and Derek, and the rest of the gang find themselves up against a new enemy: the lethal Alpha pack that has come to Beacon Hills, who have kidnapped Boyd. Not only that but a mysterious, threatening, supernatural Druid has been taking categorized people as sacrifices, killing them and absorbing their power to go against the Alpha Pack.