The premiere of "Happy Face" kicks off with Melissa Moore warmly wishing her daughter Hazel a joyous birthday. As Hazel eagerly unwraps her birthday presents, she discovers a perplexing yellow birthday card bearing the name of an unknown sender. Melissa swiftly confiscates it, casually dismissing it as a gesture from a distant uncle residing in a nursing home.
Later, Melissa heads to her workplace, the set of Dr. Greg's reality show, where she dons her hat as a talented makeup artist. She encounters Ivy, the stressed producer, grappling with a reluctant guest named Kathy, who's contemplating backing out at the eleventh hour. Ivy enlists Melissa's help to persuade Kathy.
Kathy reveals that her daughter was tragically murdered, with the police turning up empty-handed. She's torn about appearing on Dr. Greg's show. Melissa, her thoughts inadvertently swayed by the mysterious card from earlier, passionately asserts that the perpetrator must face justice. Her potent words resonate with Kathy, who decides to proceed with the show.
Melissa then ventures to a store to procure birthday essentials, including candles. On an impulse, she also picks up a prepaid phone. That evening, the Moore family gathers to celebrate Hazel's special day. After her husband dashes out for a jog, Melissa makes a covert call from the prepaid phone to a penitentiary in Oregon. Stepping outside, she leaves a stern message, warning the recipient never to reach out to her or her children again.
The following day at work, Dr. Greg summons Melissa for a private chat. He bombshells that the notorious Happy Face Killer, Keith Jesperson, has contacted the show. He claims to possess vital information about a murder and insists on speaking only to Greg or Melissa. Greg mentions he'll return the call shortly, forcing Melissa to confess that the infamous killer is her estranged father.
The phone rings, and Greg promptly switches it to speaker mode. The caller openly acknowledges his identity as Keith Jesperson and insists on a conversation solely with Melissa. He declares his desire for the media to grasp the entirety of the truth — he claims responsibility for nine victims, correcting his previous confession which stated eight. However, he stipulates that he will only disclose details about the ninth girl face-to-face with Melissa.
Ivy, driven by concern, endeavors to persuade Melissa to visit her incarcerated father. She reveals that Ben is privy to the facts, albeit her children cling to the misconception of his demise. Melissa hesitates but eventually agrees to consider the visit. Returning to her abode, she delves into a nostalgia-tinged album of her parents' photographs and retrieves cherished childhood gifts bestowed by her father.
Fleeting memories resurface, portraying young Melissa bonding with Keith, who, at that time, seemed an embodiment of a loving, typical father. Ben discovers Melissa immersed in reading letters and they engage in a heartfelt discussion. He voices his apprehension about her meeting Keith, but Melissa is steadfast in her resolve to visit for the sake of the ninth victim's family.
Melissa and Ivy subsequently venture to the prison, where they confront Keith. Ivy arranges a camera, and Keith, with a mischievous grin, signs a consent form adorned with a smiley face. Despite their inquiries for the unvarnished truth, Keith becomes irritated by Melissa's perceived detachment. He reveals that following each murder, he bestowed Melissa with a keepsake, culminating in a trampoline after the ninth victim.
The revelation sends Melissa into a state of disarray, prompting her to seek solace in the bathroom. The prison guard, initially attempting to coerce her by hinting at exposure, switches to a facetious remark, querying if she harbors the same "sick" tendencies as her father. By then, Keith's time with them has expired, and he is escorted back to his cell. Ivy persists in extracting further insights from him, to which he nonchalantly responds that Melissa is already privy to the knowledge.
Melissa and Ivy proceed to unwind with a couple of drinks at a cozy bar, where Melissa catches a glimpse of Ivy's case notes, unveiling even more chilling aspects of the perpetrator's heinous deeds. That very evening, Melissa finds herself engrossed in a news broadcast detailing his inaugural murder. A vivid flashback transports her back to a time when Keith first introduced the fifteen-year-old Melissa to the exact house where the brutal crime unfolded. As she spends the night, Melissa's eyes are drawn to a sinister blood spatter adorning the ceiling fan, which her father dismissively attributes to spaghetti sauce.
The next morning, Melissa awakens with renewed determination and informs Ivy that they must visit her mother. They head to the house, where Melissa scours through her mother June's possessions, hoping to uncover old receipts related to the trampoline. However, June reveals that she has discarded everything, pleading with Melissa and Ivy to cease their investigation.
In a private conversation, June confides in Melissa, recounting a harrowing tale of a night when, post-Keith's incarceration, an unknown man telephoned her, claiming to be watching her from within the house. She spent the entire night sitting in the darkness, clutching a knife, her heart pounding with fear. The man, she learned later, was dispatched by Keith himself, who had called to confirm his sinister plot. Despite being behind bars, June insists that Keith poses a continued threat.
During a phone conversation, Ivy catches a glimpse of a trampoline tucked away amidst a clutter of items. With Melissa by her side, they unearth it and discover a hidden address in Texas. Driven by curiosity, the duo races back to the prison to inform Keith that they have uncovered the origins of the ninth girl – Texas. They accuse him of omitting her from his initial confession due to the harsh penalty of death in that state.
Keith's narrative unfolds, detailing an encounter with a bartender in Texas whom he eventually picked up and took for a ride. Their journey included aimless driving and an intimate night together. She boasted about her aspirations to become a renowned singer, but her oversized ego irritated him to the point where he strangled her. When she didn't perish, he resorted to hitting her with a wrench and abandoned her body. He then procured the trampoline and returned home, still withholding the girl's name.
Later, a memory strikes Melissa – on the day her father acquired the trampoline, he gifted her a guitar pick. The girl from Keith's story had a guitar! Realizing this connection, Melissa contacts Ben and urges him to locate the pick inscribed with "Whiskey River." Unfortunately, Hazel eavesdrops on their conversation and, fueled by intrigue, looks into the Happy Face Killer's history.
Melissa and Ivy stumble upon heart-wrenching news about a deceased woman named Heather, who worked at a Texas bar named Whiskey River. Tragically, she was killed, and her boyfriend currently sits on death row for the crime. Realizing the gravity of their discovery, Ivy insists that they must journey to Texas at the conclusion of Happy Face Episode 1.
