Series one and two
Prior to series one, and in events broadcast as a flashback in episode seven, Howard is depicted taking ice skating lessons and listening to her parents fight. Her father Gus left the family just before Cassie started ninth grade and later became a drug addict after crashing his car; his final visit to Cassie ended with him stealing silver to fund his heroin addiction. By the time of episode one, Cassie had had multiple boyfriends, all of whom she had fallen in love with, and most of whom had coerced her into creating sexual film and photographs. She has sex with her boyfriend Chris McKay (Algee Smith) in the first episode, though she interrupts the encounter after McKay chokes her without consent, having been given the mistaken impression that she enjoyed it because of a sex tape of her he had watched. She then has to put up with him telling her that she is too sexual in episode two and with him enduring a hazing in episode three. After they visit a carnival in episode four and he tells her he is not interested in her due to her past, she takes MDMA with Daniel (Keean Johnson), mounts a carousel horse with him, and simulates cowgirl sex and loud orgasms in front of a shocked crowd. She gets back together with a groveling McKay in the next episode.
In episode six, they have sex in a dorm room, but are interrupted by a hazing ritual, after which McKay has very rough sex with Howard and Daniel reduces her to tears after she makes out with him but declines sex. After discovering she is pregnant by McKay, she tells McKay about the pregnancy in episode seven and aborts it in episode eight. In the first episode of series two, Howard accepts a ride to a new year's party from Nate Jacobs (Jacob Elordi), the ex-boyfriend of her best friend Maddy (Alexa Demie), and is sufficiently aroused by his drink-driving to have sex with him in the bathroom; she then cries uncontrollably. She then hides in the bathroom from Lexi behind a shower curtain, only for Lexi to run out of toilet paper, resort to a hand towel, and throw it in to the bathtub, where it lands on Cassie's face. Cassie then leaves the bathroom to dance with Travis (Demetrius Flenory Jr.).
Nate repeatedly blackmails Cassie and attempts to break up with her at an isolated construction site in episode two, and Lexi then writes a play partially about her relationship with Cassie, who starts waking up at 4 AM in order spend three hours changing her appearance for Nate. He gets back together with Maddy at her birthday party in episode four, causing Cassie to drink so much that she vomits. She takes part in an intervention for Rue (Zendaya) in episode five, only for Rue to reveal Cassie's affair with Nate and escape while the people involved are arguing. An apoplectic Cassie makes many attempts to call Nate in episode six and eventually moves in with him, only for him to kick her out in the next episode after an argument caused by the premiere of Lexi's play. In episode eight, Cassie interrupts the play's premiere to confront Lexi and is booed by the audience and slapped by Maddy.
Series three
By the time of series three, Howard had married Nate, moved into a McMansion with him, and got engaged to him. In the first episode, she opens an OnlyFans account, It's Just Me Cassie, with the intention of raising $50,000 for wedding flowers. Among the content she uploads to her account is pup play footage filmed by her housekeeper, Juana (Minerva Garcia). In episode two, she hires Maddy as her OnlyFans manager, publishes a baseball-themed set of nudes and footage of ice cream dripping down her breasts and of paraphilic infantilism, and deletes her account after it becomes a topic of conversation at a party Nate held to raise funds for his failing business. The pair marry in the next episode, only for Cassie to find out Nate owes Naz (Jack Topalian) $600,000 just before their first dance and for Naz to assault Nate and give Cassie a bloody nose back at their house.
In episode four, Cassie leaves Nate, moves into Lexi's apartment complex, resumes her OnlyFans career, and snorts cocaine off Brandon Fontaine (Jeff Wahlberg)'s belly button. She then uploads to her account jerk off instruction content, footage of herself dressed like a pig and of her sucking her toes, ASMRotica, and small penis humiliation. Following a macrophilic fantasy sequence in which a giant Howard walks through and destroys Los Angeles before pushing her breasts through the windows of a skyscraper containing a man masturbating to her videos, she mails dirty underwear for $50, delegates a $700 farting-in-a-jar commission to Maddy, and spouts misogyny and ableism on podcasts including a fictionalized version of Trisha Paytas's show. Much of her money during this period is wired to Nate to pay off his debts. She briefly drops Maddy after Nate swings a gig with a large influencer company, but reverses course after Maddy tells her she secured an audition for L.A. Nights, which she then organizes via Lexi. After performing a scene from Antony and Cleopatra, she gets the job as "Job Applicant", and is offered a larger role in exchange for deleting her OnlyFans account after the production's showrunner mistakes an episode six post-traumatic breakdown for improv. She then receives Nate's severed ring finger in the post.
In episode seven, Cassie loses her L.A. Nights job to production noping out of explaining her OnlyFans account and then her husband to a rattlesnake after his loansharks bury him in a grave with a small vent and kidnap her until she coughs up the $1,000,000 he owes. She follows the former by having sex with L.A. Nights actor Dylan Reed (Homer Gere) and stealing his phone to boast about the quality of her sex on his Instagram account, regaining her OnlyFans followers. After being rescued by Maddy and inventing a cover story that Nate randomly left, they spend part of the final episode discussing their next moves at a diner, before returning to Cassie's and comforting Lexi over her relationship with Rue, who had died earlier that episode. Lexi declines Cassie's offer to manage a content house to pay off her debts.
