Teen Wolf: Season 3, Episode 7

3 - 7: Currents

The Darach targets Deaton as the next sacrifice, leaving him hanging by his wrists to die. The Alpha Pack attacks Derek while Scott saves Deaton, with the help of Sheriff Stilinski. Deaton reveals Scott is a "True Alpha": a werewolf who rises to Alpha status purely by their own willpower and good character. This is extremely rare, happening every 100 years, which is why Deucalion is after Scott. Kali forces Derek to kill Boyd, which also reveals Erica's death to him, and causes Derek to break down.