- "Boyd, what do you think will happen to us during on lunar eclipse. They last for hours, you know, because it's just the earth's shadow. I wonder what will happen to us. Maybe it'll make us stronger? I hope it will make us stronger. Boyd?"
- ―Erica to Boyd[src]
Erica suffered from epilepsy her entire life. When she was in school once, she had a seizure and one of her class mates videoed it and uploaded it to YouTube. When she has a seizure, she doesn't remember it, so she didn't know what she looked like when it happened. She claims that someone suggested that they put something in her mouth. If they did, it would of broken her teeth. 
Erica and Boyd are in an empty bank vault. Erica supposing that an eclipse might make them stronger. She then attacks Kali and is killed and taken to a closet Isaac later gets thrown into a claset where he stumbles upon Erica's dead body. 
Gym class is climbing a rock wall. Stiles and blond named Erica are sent up next, and Erica looks incredibly worried. She struggles as Stiles goes up and back pretty quickly. Erica begins to cry, and then hyperventilate. Coach and her other classmates begin to worry. Erica insists she can keep going, but Allison tells Coach that she’s epileptic and Coach instructs her to just let go and let the harness bring her back down. She does, and Erica feels humiliated and miserable. Later she’s seen going back to the wall, wanting to prove to herself that she can do it. Erica doing the climbing wall and getting much further this time, but she’s not harnessed. Scott feels something weird and appears just in time to catch Erica after she falls off the wall from a seizure. Ms. McCall is taking care of Erica in the hospital. A darkly clad figure, later revealed to be Derek pushes her gurney away into the morgue. Derek has her medicine and is talking about the horrific side effects, refusing to tell Erica who he is and why he’s there, and is in her space from the start. They discuss her seizures. He asks "What if I told you that all of this could go away?" He appears to be using sex appeal to get to her, and she asks how can he make it go away. His eyes go red as he smiles. The newly turned Erica enters the cafeteria in leather, extremely high heels, and heavy makeup looking like a bombshell and everyone stares. She makes an entrance, steals a kid’s apple, and walks out. Stiles and Scott follow Erica out to see her getting into the Camaro with Derek, who’s gives them an unnerving smile before speeding away. Erica is checking her makeup in school the next day when she’s approached by Scott. Scott wants to know who’s next to be turned, but Erica ignores the question and tells a story about how a bunch of idiots at their school filmed one of her seizures and put it on YouTube to laugh about her and how it destroyed her self-esteem. It seems as if she’s trying to explain why she asked for the bite. When Erica notices Allison watching she gets handsy just to make them both angry. Stiles arrives at Boyd’s house, but doesn’t get an answer. Erica shows up and uses her sexuality at a tool to get him nervous before knocking him out with a car part. At the Ice Rink, Scott and Boyd are talking, Derek shows up with Erica and Isaac, who are essentially acting as guard dogs. Derek asks Erica and Isaac how the bite has changed them before prompting them to attack Scott when he refuses to cooperate. Scott incapacitates them quickly because they are young and inexperienced. Boyd watches and Derek seems amused as if this is what he planned. He then shifts and wipes the floor with Scott to make a point, pinning him to the ground with a boot at his throat before walking out. Boyd’s still just watching and is a little concerned now, but he’s already got the bite, and he says he wants to be like Scott. 
Isaac, Erica, and Derek are training. Although the gymnastics are pretty, both Isaac and Erica continually get slammed into the ground by Derek, who isn’t impressed with them by any means. Boyd watches with concern. Frustrated, Derek asks if any of them will do anything that isn’t completely predictable and Erica gets up and kisses him aggressively in response. Derek plays along for a few seconds before throwing her to the ground. Isaac whines about needing to heal and Derek turns snaps his forearm knowing that it will heal eventually before launching into a speech about how the betas need to learn everything he knows ASAP with new threats in Beacon Hills. Later at the school, Erica follows Stiles and surprises him in the principals office. Erica brings Stiles to Derek, who’s at the pool. Derek asks him about what happened at the mechanic’s and Stiles responds with sarcasm. Derek’s response is a thinly veiled threat. Stiles begins to tell Derek and Erica about the monster, which shows up as Stiles describes it. Derek immediately goes onto the defensive, and the monster hits him and Erica with the paralytic venom. After the creature is gone, outside the school, Derek and Erica return with Derek stating that this monster is called a “kanima”, which he figured out when it was confused by its reflection. Derek tries to explain the difference between it and werewolves since they are both shapeshifters, and Stiles supplies that it’s an “abomination”, which Derek agrees with. 
At the school, Jackson tries to lift too much weight and it nearly crushes his chest. Erica appears over him and lifts the bar from his chest with one hand. Erica delivers Jackson to Derek in the subway tunnel. She and Isaac hold him, while Derek asks him what happened to him on the night of the full moon. Jackson claims nothing happened, but Derek can tell he's lying. Derek starts to put on a black leather glove. He tells him that he can prove it and says that he taped himself. Derek and Isaac find this amusing. Jackson makes fun of Isaac for having an existential crisis and says the he was preparing for the gift Derek promised. He tells him he'll get the video, even though he knows that the video is missing two hours of footage. Derek picks up the piece of broken mirror that Scott used against the kanima and claims that he has a better idea. "You know, Jackson, you've always been kind of a snake. And everyone knows a snake can't be poisoned by its own venom." Derek then tips the glass toward Jackson's mouth. Erica and Isaac hold his jaw open, so he swallows a drop of the kanima toxin. The effect is immediate, and Derek is clearly disappointed that Jackson passed the test. Later at school, Jackson then overhears Erica talking to Isaac, confirming that Derek wants something done during Chemistry class. Isaac advocates just killing their target, while Erica says she's going to test her first, they are referring to Lydia. In chemistry, Erica and Isaac come into the room, Scott realizes that the test is going to happen right then. Scott quickly takes the empty seat next to Lydia. Mr. Harris tells Erica to take the first station, and nearly all of the people in the room raise their hand to be her partner, even though Harris didn't ask for volunteers. Harris pairs Erica with Scott. Scott pours some blue liquid into a beaker and asks Erica to wait before she does whatever she's planning. Erica tells him to talk to her instead and leans in close, but Scott pulls away. Erica can smell Allison all over Scott and realizes they aren't as broken up as they try to appear. She puts her hand on his leg and tells him that she'd be wanting him all the time. Scott tries to take Erica's hand away, but she gets rough with him. Just then Harris rings the bell and tells them to switch stations. Allison is sitting next to Erica and asks what they're planning to do. Erica tells her that the better question is what is Lydia going to do to all of them. She then says that Allison and Scott are cute together but she doesn't think it's going to last. Allison counters by asking if she thinks she can hurt her by sliding her hand up Scott's thigh. Erica then puts her claws on Allison's thigh and asks if she wants to have a girl fight in the lab. She digs her claws in, and Allison reacts in pain but doesn't make a sound. Isaac confirms that the venom doesn't effect Lydia. Isaac and Erica flounce down the hallway of the high school. Isaac runs his claws along the lockers, scratching off paint and causing sparks. They head into the library looking for Lydia. Isaac grabs Matt and demands to know where "she" is. Meanwhile, Stiles, Lydia, Jackson, and Allison head out of the library for a study group. They all get into Stiles's Jeep and drive away. Later at night, Derek and his pack surround Scott's house. Erica breaks into Scott's room, and Allison has her crossbow aimed at her heart. Erica taunts her, saying that she thinks Scott will be an easy boyfriend to steal. Allison shoots a bolt, and Erica catches it. Allison had covered the bolt in kanima venom, so Erica goes down. Allison kneels down next to her and brushes her hair back. "I thought you were psychic. Bitch." Just then, Scott throws Erica and Isaac out of the front door. The kanima crawls on the roof and roars at them all. Derek tells Boyd to get Isaac and Erica out of there. 
In the subway station, Isaac asks Derek why they need Scott and Stiles's help. "Because it's harder to kill than I thought, and I still don't know who it is." He thinks Scott and Stiles might, so he needs Erica or Isaac to start a friendship with one of them. Erica muses over which one. Derek doesn't care. Isaac points out that the full moon is coming. Derek is aware and opens up a trunk full of restraints. He pulls out chains and straps. Isaac says they were supposed to be learning to change whenever they wanted. Derek tells him that there hasn't been time. "But if you have to lock us up on the full moon, that means that means you're alone against the Argents," Isaac says. Derek points out that they haven't found them, but Isaac thinks it's only a matter of time. He suggests forgetting about the kanima. Later at the school Erica appears, eyeing up Stiles. Erica slams him against the wall and demands to know why he's asking those questions. "Why are you bringing out the claws on camera?" he replies. She puts them away. Erica tells him that if he wants to know about Jackson's real parents they're a half mile away in Beacon Hills Cemetery. Stiles chases after Erica and asks her if she knows how Jackson's parents died. "Maybe. If you tell me why you're so interested." Stiles doesn't say anything, but Erica realizes that Jackson must be the kanima. Stiles tries to explain to Erica that there's a lot more going on that they don't know about. "And just because you got the alpha bite makeover doesn't give you license to go around destroying people." "Why not? That's all anybody ever used to to do me. I used to have the worst crush in the world on you. Yeah, you, Stiles, and you never once even noticed me. Exactly how you're not even noticing me right now." Stiles was actually looking at the water coming out of the locker room, and then Scott comes flying through the door. Erica restrains Jackson, while Stiles holds back Scott. Mr. Harris comes down the hall demanding to know what's going on. Mr. Harris demands explanations from Scott and Stiles. When he doesn't get anything, he hauls Jackson, Stiles, Scott, Allison, Erica, and Matt in for detention. In the library, Jackson starts getting one of his headaches that indicates he's going to change. He gets up to go to the bathroom, much to Mr. Harris's concern. Mr. Harris follows Jackson. As soon as he's gone. Stiles and Scott sit with Erica. Scott asks her how Jackson's parents died. She tells him it was a car accident. Erica's dad was the insurance investigator. Jackson will be getting a huge settlement when he turns 18. Stiles is incredulous that Jackson will become even richer. Erica offers to look up the insurance report in her dad's inbox. Jackson comes back into the library. Stiles and Erica are reading the report on her laptop. They figure out that Jackson's parents died before he was born and he was delivered from his mother's body at the hospital even though she was DOA. The kanima leaps from bookshelf to bookshelf, destroying the ceiling and overhead lights. Scott starts to shift and calls out to Erica. Jackson takes down Erica and then appears behind Scott. He's in a half-transformed state. Stiles goes to Erica and discovers that she's having a seizure. Stiles says they need to get Erica to a hospital. Erica insists that they take her to Derek instead. Scott helps Stiles and Erica. Derek brings Erica into the subway car, followed by Scott and Stiles. Derek tells them to hold her up, and Stiles moves so they can lean Erica against him. Stiles asks if she's dying. "She might. Which is why this is gonna hurt." He takes Erica's wrist and breaks her arm. Stiles is horrified. Derek tells him that it will trigger the healing process. He claims he still has to get the venom out of her system and starts squeezing her arm, where presumably her shattered bones have broken through her skin causing her to bleed. 
Isaac and Erica head into the rave. Erica finds Jackson and distracts him by touching his neck and starting to dance with him. Isaac joins in, and it's the three of them dancing. The boys kiss Erica and eye each other. Stiles arrives at the location where Erica and Isaac have taken Jackson. He asks if Jackson is okay. Isaac gets out his claws and attempts to slash Jackson, but Jackson catches his arm and twists it without seeming to be conscious. Isaac escapes, holding his hurt wrist. He complains that the ketamine was supposed to put Jackson out. Stiles figures this is all they're going to get. Jackson's eyes open and he starts talking. "I'm here. I'm right here with you." Outside the rave, Isaac and Erica come out, but they can't leave because of the barrier. 
At the subway, Derek tells them that the price they pay for their power is bloodlust on the full moon. Erica quips that it's a good thing she had her period last week, then. Derek smirks and holds up a crown of spikes that she will get to wear. Derek chains Isaac, Boyd, and Erica up in the subway car. Isaac asks why Erica has to wear the headband, and Derek explains that Erica will be able to withstand more pain than either of the boys. Isaac holds her while Derek screws the bolts into her head. Boyd looks really upset. Isaac, Boyd, and Erica all shift and strain against the chains. Derek calls Scott and leaves him a message that he's probably going to need some help with the betas. The betas start breaking out, and Derek whips out his claws. Erica is the first one to get free, and she takes a swipe at Derek. While Derek is occupied, Isaac leaps out the subway car window, and then Boyd attacks from behind. Erica and Boyd get Derek pinned to the ground and attack him. Derek manages to chain Erica back up to one of the poles in the subway car. Isaac comes back in and attacks Boyd, but this time he's under control and doing it to help Derek. They nod at one another in recognition. 
Boyd and Erica are walking through the preserve. Erica says that Derek told them to be back before sun up, but Boyd stops her because he hears something. They think it's a wolf howl. Boyd doesn't think the howl sounded like Derek. A bunch of howls go up all around them. Derek is in the Hale House looking through some old books when Boyd and Erica arrive. He knows they've decided and asks them when. Boyd replies that they'll do it tonight when everyone is at the game. They want to run away. Erica says that she only turned 16 a month ago and would like to get her driver's license. Derek replies that he told them there would be a price. Boyd says that they didn't know it would be this dangerous. Derek says that they need to be in a pack to survive, and Boyd tells him that they know. That's when Derek realizes that they want to look for another pack. He asks them how they're going to find one. Boyd thinks they already did, which catches Derek off guard. Boyd and Erica tell Derek about the howling that they heard. Derek explains the Beau Geste effect, where wolves can modulate their howls so that two can sound like twenty. Boyd and Erica are unswayed. They say they're leaving, but Derek says they're running. "Once you start, you don't stop. You'll always be running." It's another one of his speeches from experience. Erica takes Boyd by the hand and pulls him away. In the woods, Chris, Allison, and some other hunters ride their 4-wheelers through the preserve. Allison plays a recording of wolves howling. Boyd and Erica are hiding behind a nearby tree and know that they've been tricked. They clasp hands. Erica and Boyd run from the Argents. Allison hops off the 4-wheeler and shoots Erica in the leg. Boyd goes back to help her, but Erica screams at him to keep running. Allison bears down on Erica and shoots to kill, but Boyd grabs the arrow before it hits. Allison fills him with arrows. Erica cries and begs for her to stop. Erica begs Allison to stop, and Chris shoots the bow out of her hands. Boyd collapses. They then get taken to the Argent house where their tied up in the basement. 
One of Gerard's hunters opens the door to the basement and throws Stiles down the stairs. When he gets up, he hears whimpering in the darkness and backs up against the wall. He fumbles for the light switch. When he turns it on, he sees Erica and Boyd strung up from the ceiling with their mouths taped shut. Stiles shushes Erica as he tries to untie her. He touches the wires at her wrists and gets electrocuted. The lights in the basement flicker. Gerard comes down the stairs and tells Stiles that the wolves were trying to warn him that the bonds were electrified. Later, Chris goes to talk to Boyd and Erica. He tells them that his family has been hunters for a long time, long enough to learn that a certain level of electric current can keep them from transforming. At another level they wouldn't be able to heal, and at another their strength is reduced to that of a regular human. He claims that their scientific understanding of werewolves makes them less supernatural. The lines between natural and supernatural start to blur. And he tells them that sometimes you can be surprised which side of the line you end up on. Chris flirts with adjusting the settings on the electrical current holding them hostage, but ultimately doesn't change it because he hears someone coming. Later, Boyd and Erica are free and running through the forest. They pause to catch their breaths, but they are suddenly surrounded by a group of werewolves. 
The Alphas walk through the bank, and Kali thinks she’s smelled something, but Allison spills ammonia in the closet, throwing her off. Looking around the closet with her phone’s flashlight, Allison finds Erica’s body. Later, Derek goes into the closet and removes her body, taking her in his arms out of the Bank. It is unknown what happened to her body after this.