As seems to be a recurring theme in their lives, Stiles comes to Scott with a plan. He's eavesdropped on his father's calls and learned that they found half a dead body in the woods. Stiles is gleeful at this macabre news and drags Scott out to investigate. While they are in the woods, they get separated, and Scott is bitten by a Werewolf. Scott doesn't know what's happened to him, but Stiles at first jokes, then really suspects, that lycanthropy is actually the source of Scott's new powers.
Stiles takes it upon himself to research Werewolf and try to guide Scott in developing his powers. Stiles is both thrilled that his friend has had something this cool happen to him and worried that Scott isn't taking proper precautions. He warns him that anger and a rapid pulse will give rise to bloodlust. Once they have determined that Derek Hale is the killer, Stiles takes it upon himself to provide evidence for his father to perform an arrest. Scott suspects there's a body buried at the Hale House, and Stiles drives them out there with shovels to discover the truth. He recognizes the wolfsbane connected to the body, and because of his tinkering, the black wolf they found buried turns into the body of a girl.
Like Scott, Stiles also starts showing more interest and bravery in developing his social life. He has harbored an intense crush on Lydia Martin since they were small but has never taken any steps to be noticed by her. This starts to change, as Stiles introduces himself and attempts to make Lydia respond to his presence.
Stiles isn't shy about sexuality, and despite being in love with Lydia, asks his male friends if they find him attractive.
Stiles does his best to support Scott through the changes in his life. Despite earlier suggesting that Scott break off a date with Allison, Stiles gets behind the idea that Scott should have as normal a life as possible. He doesn't believe that Scott would kill someone and that this fear should keep Scott from seeing her. Like Scott, Stiles still believes that Derek is the murderer the police are looking for, and he doesn't think Scott should go to him for lessons on being a Werewolf. Even though they've always been a team, Stiles starts feeling like he's Robin to Scott's Batman, and he's not appreciative of the sidekick role, presumably because he was always Batman before.
When Derek gets shot with a wolfsbane bullet, Scott makes it Stiles's job to take care of him. Stiles is appalled and at first only helps Derek under duress. He claims that he isn't scared of Derek but always gives in to Derek's threats. Stiles displays a mix of concern and apathy toward Derek while Derek's condition deteriorates. It's clear that he doesn't want to deal with this, but equally that he doesn't want Derek to die in front of him. He continually updates Scott on Derek's status and urges him to hurry. Derek's final solution to the wolfsbane poison is to have Stiles cut off his arm with a saw. Terrified and not sure he will be able to withstand something so horrific, Stiles is about ready to do it when Scott returns with the cure. After Derek recovers, Stiles celebrates the victory more than either Scott or Derek seem to.
Stiles was having fast food with his father in his police cruiser when the call comes in about an attack at the video store. Stiles goes along on the call and is surprised and concerned to see Lydia and Jackson at the crime scene. He gets angry when Jackson starts belittling his father but breaks the tension by pointing out the dead body when it is wheeled out. The next day at school, Stiles quizzes Danny on what he knows about what happened. Danny isn't interested in talking to him but answers his questions anyway. Stiles then asks if Danny finds him attractive, but Danny doesn't answer. Concerned because Lydia wasn't in school at all, Stiles heads over to her house. She's high on medication, which makes her more amenable to his company than she would otherwise be. Stiles is thrilled at the attention and touching until he realizes that Lydia thinks he's Jackson. While he's there, though, he manages to spot a video on her phone of the alpha. Stiles steals her phone and tries to decide what to do.
He calls Scott numerous times but gets no answer. In the end, Stiles deletes the video, despite how much it pains him to destroy evidence. His grades are good enough that he doesn't have to attend the parent-teacher conference with his father. Instead, he spends the evening home alone researching the Hale House fire.
Following the parent-teacher conferences, Stiles isn't talking to Scott because he let his father get hit by a car in the parking lot. He tries to maintain a stony silence in the face of Scott's distress, but when Scott finally tells him that he's training with Derek, Stiles can't take it anymore. He doesn't trust Derek and resolves to teach Scott how to control his shifts on his own. Stiles already knows that the shifts are connected to heart rate, so he steals a heart rate monitor from Coach Finstock and sets up with Scott in the lacrosse field. Stiles throws lacrosse balls at Scott until he gets so upset he starts to shift. It's both an outlet for his anger and a way to help his friend.
Scott keeps it together despite the pummeling. In Economics class, Finstock starts to berate Scott over his grades and lack of participation. He's still wearing the heart monitor, and Stiles watches the counter go up. When Scott's heart rate inexplicably starts to go back down, Stiles notices that Allison is holding his hand. This leads him to the conclusion that Allison is actually good for Scott's control. He puts this theory to the test by keying a senior's car and making them think Scott did it. Scott gets beat up, but by focusing on Allison, he doesn't shift.
When Scott decides that he finally needs to confront the alpha, he and Stiles head to the school after hours. Stiles sets up the PA system, and Scott howls. Stiles thinks it's 12 kinds of awesome how loud the howl was, although Derek, who was waiting outside, is less than impressed with their attempt to draw attention to themselves. Stiles tells him not to be a sour wolf. The alpha attacks Derek, and Stiles and Scott assume he is dead as they run into the school to hide.
Stiles risks his life to get the bolt cutters so they can lock the doors shut. After running for their lives, Stiles comes around to Derek's opinion that Deaton must be the alpha. Scott doesn't believe it, though. Stiles consistently comes up with on the spot plans as they search for an escape route. He is conscious that windows leave them exposed and directs them toward more closed spaces. It's his plan that momentarily traps the alpha in a small room in the basement, although his curiousity gets the better of him, and his taunts enrage the alpha all the more.
Stiles refuses to call his father through most of the ordeal, because he is afraid that it will only get his father killed. This causes a particular tension because he cannot explain to Jackson, Lydia, and Allison why he is so opposed to such an obvious solution to their problem.
Stiles seems somewhat appalled when Scott tells everyone that Derek has been killing everyone in town, although he has shown little concern for Derek up to this point.
Eventually, Stiles does leave a voicemail for his father, and they are rescued by the Sheriff's department. Stiles thinks they've done a superb job keeping themselves alive through the night, but Scott convinces him that it wasn't their wits that saved them. The alpha didn't want to kill them; it wanted Scott to do it, and Stiles is struck speechless with horror when Scott tells him that he almost did.
Stiles tries to cheer Scott up by taking him out to the woods and getting him drunk. Scott doesn't seem to be affected by alcohol, but Stiles gets himself pretty wasted. Stiles is aware that the full moon is tomorrow and tries to keep tabs on whether Scott's aggressive behavior is because of the break-up or because of the effects of the moon. He has a plan to chain Scott up to keep him from hurting anyone.
At school, Stiles waits for his father to come out of the principal's office so he can tell him to extremely careful as they hunt for Derek. He can't tell his father why this night, above all others, is dangerous, so he instead has to play off his dad's inexperience with the kind of serial killer they currently believe Derek to be. When Scott suddenly leaves the lecture hall in the middle of his test, Stiles runs after him. He finds Scott winding up toward a panic attack and gives him his inhaler to make him think he's having an asthma attack instead. The interruption of the panic keeps Scott from having a full blown episode. Stiles reveals that he used to get panic attacks often after his mother died.
At lacrosse practice, Coach Finstock informs Stiles that he will have his first chance at first line. He is overjoyed and cheers and can't wait to actually get to play after so long on the bench. Feeling high off of this, he asks Scott to ask Lydia if she likes him. Stiles wants to know if there's any chance that his crush from 3rd grade will actually turn into something. Instead, Scott makes out with Lydia, which Stiles figures out when he sees Lydia's lipstick messed up later on.
Stiles notes Scott's behavior becoming more erratic and aggressive throughout the day, and he tries to believe that it's all due to the full moon and not to Scott becoming a crappy friend. When Stiles goes to chain Scott up in his room, he reveals that he came prepared and handcuffs Scott to the radiator. He gives him some water in a dog bowl and yells at him for having betrayed him with Lydia. When he can't take it anymore, he goes and sits in the hallway and listens to Scott struggle, upset at the entire situation.
After Scott breaks free, Stiles goes looking for him but instead comes upon a crime scene in the woods. For a second, he thinks his father has been killed, and he hugs him fiercely when he sees he's okay.
Thanks to Scott pointing the finger at Derek as the murderer, again, Scott and Stiles have to try to save him from the police, as well as the Argents. They learn that Allison's necklace has something to do with the murders, and Stiles tries to help Scott form a plan to get it from her. In the end, he suggests simply stealing it. When he gets home, Stiles finds Derek hiding in his room. He covers for him with the Sheriff, who is so proud that Stiles is finally going to get to play in a lacrosse game. Once his father is gone, Derek threatens Stiles, but Stiles snarks back at him about roughing him up in his own house. Further, he reveals his plan to trace the text that brought Allison to the school the other night, since it clearly wasn't from Scott.
The plan involves getting Danny to run a trace. Stiles read Danny's arrest report for cybercrime and begs him to help. When Danny refuses, Stiles gets Derek to take his shirt off so Danny can leer. Derek is aware of what he's doing, and Danny is aware that it makes him a bad person, but in the end Danny agrees to help. Stiles is quite proud of his improvisational bribery. When the text points them in the direction of Mrs. McCall, Stiles heads out with Derek to investigate.
There is no way that Stiles is going to be able to play in his first game if he's helping Derek, but he makes the sacrifice anyway, which Derek appears to acknowledge in the way he looks at him. It's short-lived, though, as Derek then slams Stiles's head into the steering wheel for having treated him like a piece of meat back in his room with Danny. When Stiles goes into the hospital to investigate, he tells Derek that Peter's room is empty. This is enough information for Derek to piece together that Peter is the alpha and warn Stiles to run. Stiles turns around to find Peter waiting for him and believes he's going to die. Derek saves Stiles from Peter, and Stiles does his best to run away.
He must escape and leave Derek behind, because the next time he shows up is after Derek and Peter have visited Scott in the boys locker room post-game. The next day, Stiles and Scott save Jackson from Chris Argent. That evening, Stiles sees his father looking through case files and gets him drunk to get information out of him. He's aware of how horrible it is to do that to his father, but he wants the information more and learns that all the murder victims were connected to the Hale House fire and were likely perpetrators. His father tries to tell him that he misses when they used to talk to each other, but Stiles is too preoccupied to really listen, until his father mentions his mother. They never talk about her, and Stiles stops dead at the mention of her. He pays closer attention to his father then and stops him from getting more drunk.
When Scott learns that his mother is going on a date with Peter, he calls Stiles and uses him as a pawn to break up the date. Stiles rearends Peter's parked car, which earns him stern words from Mrs. McCall.
Following Scott's rescue of Jackson, Stiles argues for letting the Argents take care of Peter as they seem to want to do. Scott can't let that happen, though, because Peter has threatened Allison. Scott can't find his phone, which Stiles suggests he probably lost during the fight with Derek. He later surmises that Derek took the phone on purpose, because he knew he was going to be captured and was giving them a way to track him down. Or, more like, for Stiles to track him down, because Stiles had already pulled off the trick with tracing the text.
Much to his surprise, Stiles ends up going to the winter formal with Lydia, although only because Allison makes Lydia ask him. Stiles finally admits to her that he's had a crush on her since the third grade and tells her that he knows how smart she is. She's surprised and charmed enough to dance with him, although she can't stop thinking about Jackson. Stiles takes the let down pretty well. When Jackson comes back into the dance not having found Lydia, Stiles goes looking for her and watches as Peter attacks her.
He begs for her life and then tells Peter about his idea of tracking Derek through Scott's phone. Peter hauls him off to a parking garage so he can activate the GPS.
Despite all his threats, Peter offers Stiles the Bite. Stiles looks tempted and only pulls his wrist back at the last moment. Peter tells him he's lying to himself if he thinks he doesn't really want it. After he's released, Stiles runs to the hospital to check on Lydia. His father is furious with him, but Stiles tells him that everything is connected to Derek and the fire. Stiles grabs Jackson, but they are assaulted by Chris Argent. Stiles tells Chris that he thinks Kate broke the code and burned the Hales. Chris lets him go. Stiles and Jackson go make some of the molotov cocktails that Lydia tried to mix up earlier. They meet Scott at the Hale House and help set Peter on fire.