Brett is a born werewolf, like his sister. When Brett was younger, his family died in a house fire except from his sister. From then on, Satomi took him and his sister in and they both became part of her pack as she cared for them.
Brett and his school arrive in Beacon Hills to play lacrosse against the Beacon Hills team. He starts on Liam outside of the school for destroying their coaches car. Later at the game, Brett battles with the other team to win the game. Brett is injured by Garret and is taken inside where he is attached and is about to be killed when Scott interviews. But Brett was only just the bait, Violet was after Scott all along. She wraps her heat wire around Scott's neck but is overpowered and beaten down.
Stiles and Derek have taken Brett to the Animal Clinic and are trying to hold him down so Deaton can make an incision. Brett is seizing and foaming yellow at the mouth. "What the hell is happening to this kid?" Stiles asks. Deaton replies that he's been poisoned by a rare wolfsbane. As they struggle to hold him, Stiles gives Derek a surprised kind of look while Deaton tells them that if they can't hold Brett still the incision might kill him. Brett jerks and throws both Stiles and Derek off. Brett gets up and starts to run, but Peter cuts him off and punches him in the face, knocking him out. Stiles kneels next to Brett and claims that he isn't breathing. Deaton cuts the center of Brett's chest, releasing a puff of yellow gas. Peter watches as Derek's wounds heal. Deaton says that Brett will be okay but probably unconscious for a while. Brett starts to mutter something and after a few seconds it's loud enough to recognize as the same mantra Demarco used: the sun, the moon, the truth. Deaton tells them that it's Buddhist, and Peter realizes that their alpha must be Satomi Ito.
Bertt and Lorilee are running from the assassins who are shooting at them with arrows. Kira arrives and helps them escape by blocking the arrows and taking them all somewhere else where she thinks is safe, so she can meet up with Scott to come up with a better plan. Scott brings the pack to Argent's warehouse where Chris approaches and points a gun at Brett. Brett tries to attack but Scott tells him to back down as Chris is one of the good ones. They are talking about the dead pool when Brett says “What if it doesn’t end until we’re all dead?” Derek replies that they will send a message. “It doesn’t matter if they’re a professional assassins, hunters, or an amateur who just picked up a gun. Anyone who thinks they can hunt and kill us for money is gonna be put on another list. Our list. They get to be put on our dead pool.” The hunters come and Brett and the pack fight them, until Malia and Stiles turn off the dead pool. The hunters get a text, and they all start to leave.
Brett's lacrosse team is against the Beacon Hills team. At the game, Brett knocks Liam down with a brutal and illegal hit. Liam demands to know why he did that. "Because you're afraid. I can smell it on you from across the field." After his school won the game, Brett finds Liam in the locker room and asks him if he's okay. Liam points out that they lost. Brett asks again if he's okay, so Liam asks why he helped him. "Because of Scott. He saved me. He saved all of us." Brett tells Liam that he's lucky to have an alpha like Scott, who earned his power. He says that Liam is strong because he endures. "You're lucky to have him." "Then why isn't he here?"
Liam and Mason go to Brett, who is on the field, practicing lacrosse shirtless, for information. While they listen to him, Liam finds out that Tracy is wearing a necklace similar to the one in the hole he fell through. At night, Liam and Brett walk through the woods and Mason finds the hole, but no necklace was found. Brett tells them that the hole isn't a sinkhole, Tracy was buried in there.
Brett was spotted by Liam and Mason at a club called Sinema, supposedly a gay club. He was first dancing with a girl but soon changes the girl to a guy revealing that he is bisexual. After Mason is taken, Brett helps Liam out and gets slashed in the stomach in the process.
Mason and Brett are sitting on the bleachers at the school talking about the supernatural warning signs they can look for. Brett offers that able to see in the dark is a good clue. Brett asks Mason what the deal is between Hayden and Liam. Mason explains that in sixth grade Liam was getting into a figth with another kid. Hayden accidentally walked into the fight and got punched. She has a broken nose in her yearbook photo. But she hit Liam back, and he had a broken nose in his photo too.