Derek Hale (Season 1)

Prior to the events in the first episode, Wolf Moon, Derek returns to Beacon Hills after the death of his sister.

Scott McCall initially blames Derek for biting him and turning him into a werewolf. Derek claims he was not responsible, and that another werewolf, The Alpha, is the one who bit Scott. Derek assumes the role of a mentor to Scott, explaining what it means to be a werewolf and how to control his new instincts and nature. He also attempts to keep Scott away from The Alpha, explaining that the beast wants Scott to kill with him and join his pack. Derek tells Scott that if The Alpha finds him, Scott will have to kill with him or be killed.

Kate Argent returns to Beacon Hills seeking the Alpha in Magic Bullet. She is part of a family of werewolf Hunters and shoots Derek in the arm on her first night back in town. The bullet was tipped with Nordic Blue Monkshood (wolfsbane). The bullet poisoned him, bringing him near to death. Scott helped to save his life by stealing another of the bullets from Kate’s bag during dinner with the Argent family. Derek cured himself by burning the wolfsbane from the bullet and putting the ashes on his wound.

Lead hunter, Chris Argent, believed Derek knew the identity of the Alpha and ordered that he be tracked in hopes he would lead the hunters to The Alpha, but when Derek revealed to Kate that he did not know, she tried to kill him (contrary to the hunter’s moral code to not kill any werewolf not proven to have spilled human blood). In Heart Monitor, Derek was attacked by The Alpha at Beacon Hills High School. The Alpha attacked from behind and lifted him off the ground as gouts of blood poured from his mouth. There was much speculation that Derek was dead after this attack but he returned two episodes later.

At the end of Lunatic, on the night of the full moon, Derek seemed fully recovered and stopped Scott from attacking Jackson and Allison. Then, the two werewolves fought in the woods until Scott regained control of himself. Scott asks if there is a cure and Derek says he has heard of one, killing the Alpha responsible for the bite, but that he doesn’t know if it is true.

The ninth episode, Wolf's Bane opens with Derek saving Adrian Harris from the Alpha. He is then forced to go on the run from hunters and the law because Scott has told them that Derek is responsible for all the mysterious attacks and claimed that he had tried to kill the young cast during Night School.

Derek ends up hiding at Stiles’ house. The pair lures Danny over to help them track down the cellphone responsible for sending a text that led Allison into danger during Night School. Stiles claims Derek is his “cousin Miguel” and uses Danny obvious attraction to Derek to convince the young man to help them hack the cell phone. Danny tracks the text to a Melissa McCall’s computer at Beacon Hills Hospital where Derek and Stiles find out the Alpha is actually a fully recovered Peter Hale. The two fight and Peter claims he killed Laura by accident and that all the other killings have been revenge against the men who helped Kate kill their family.

In Co-Captain Derek seemed to have joined forces with his uncle and worked to eliminate Jackson because he had learned Scott’s secret. At the end of the episode Derek was captured by Kate and was chained in a cellar beneath the Hale House. She used an electrical device to torture him.

In Formality Kate introduces Allison to the concept of werewolves by showing her Derek on the torture rack. Scott rescues Derek in Code Breaker. They, along with the rest of the gang and Chris Argent, attack the Alpha. The kids burn and cripple Peter but it is Derek, over the protestations of Scott, who delivers the death blow, slashing his claws across the Alpha’s throat killing him and assuming his position and powers.

Derek is later confronted by Jackson Whittemore who demanded to be bitten and turned into a werewolf. Derek advances toward the boy and shows his fangs but the scene cuts away without revealing if Jackson got his wish.