The drama unfolds in the first episode of All Her Fault's inaugural season as Marissa races to an address, heart pounding, to collect her son, Milo. Alas, Milo is nowhere to be found. The woman claiming to have him, Jenny, is unresponsive. Marissa reads the text from Jenny again, confirming she's at the correct address. The woman at the house, Esther, welcomes Marissa in as they try to unravel the tangled web of misunderstandings. In the text, Jenny mentioned her son, Jacob, and Milo would be with the nanny.
Esther inquires if Marissa is familiar with Jenny, and she admits they met at the school fair where they clicked despite Marissa never visiting Jenny's home before. Marissa assumes it was a case of autocorrect gone awry and calls her nanny, Ana, to verify the address. Alas, Ana is currently out of town for a wedding, and Marissa can't reach her.
Esther suggests they call another parent from Milo's class to see who picked him up. Marissa calls Sarah, the parent representative, and asks for Jenny's other number. Sarah is confused since she's with Jenny's son. She sends Marissa Jenny's number to clear the confusion. Marissa calls Jenny, who is baffled as she's at work and didn't send any message about a playdate. Esther takes over the call as Marissa starts to panic.
Marissa then calls her husband, Peter, who hasn't picked up Milo either. Marissa and Esther rush home, their hearts heavy with fear, hoping to find Milo there. Alas, they only find Brian, Peter's brother, who lives in the guesthouse. Peter arrives shortly after and starts to comfort Marissa.
The couple calls the police, and the investigation commences. According to Marissa, she dropped Milo off at school that morning. Currently, they are unable to reach Milo's teacher as well. Marissa explains that she received a text from Jenny earlier in the afternoon suggesting a playdate after school. Despite not wanting to cancel a work meeting, Marissa appreciated the help. With her nanny out of town for a wedding, Jenny's offer felt like a blessing from above. The police circle back to the text and ask if Marissa verified it was indeed from Jenny. Unfortunately, Marissa never saved all the school moms' numbers on her phone. She assumed the text was from Jenny due to its signature-like style.
In the interim, Jenny reaches out to her husband, filling him in on the bizarre call she received. She implores him to hustle and fetch their son from Sarah's house, fearing a tardy arrival would tarnish their family's reputation. She then calls Sarah to apologize for her husband's tardiness, understandingly accepted but with a subtle attempt to steer the conversation towards the school fundraiser, which Jenny skillfully deflects with a change of subject to Marissa.
Sarah, however, cannot resist the urge to gossip, speculating on the identity of the sender of the message and criticizing Marissa for employing a nanny. Flashbacks reveal the start of the school year when parents met to discuss their kids' calendars. It was during this meeting that Marissa called out Sarah for unnecessary events on the calendar, a moment Jenny found amusing and smiled at Marissa in agreement. Meanwhile, Ana and Carrie met at the playground.
Back at Marissa's residence, the police grill those close to the family. Brian joins the couple for support and offers his statement. Peter, distraught with worry, tells the police that his sister is on her way and pleads for them to do everything possible to secure Milo's safe return. Colin, Marissa's friend and business partner, arrives as well, offering to manage Marissa's work in the interim. Throughout this time, Marissa is persistently trying to reach out to Ana, only to find her phone on a sofa on the patio, a startling discovery.
Meanwhile, Jenny meets with Alex to discuss her proposal for Lee Logan, a client she hopes to sign in the publishing industry. Unfortunately, her husband's incessant text messages interrupt, asking numerous questions about their son's nighttime routine. Jenny takes a momentary break to call him back and speak with her son, who incessantly longs for her presence. She promises to be there to tuck him in with a motherly hug.
In the midst of chaos, the police discreetly bagged Ana's phone as a crucial piece of evidence. As the scene shifted, Ana unexpectedly materialized, surprised to find everyone inquiring about Milo's whereabouts. Just then, a new lead emerged: Milo had been picked up by a woman named Carrie Finch, revealed to be Jenny's trusted nanny.
Jenny rushed home, her heart pounding with fear, to find a police car parked outside. She sprinted to her son's room, relieved to see all was well. The police inquired about Carrie's routine, and Jenny shared that Carrie had been with them for three months, never exhibiting violence towards Jacob—except for one misunderstood incident where Jenny thought Carrie was about to lash out at her son. Later, she realized Carrie was merely swatting a fly.
The police hinted that Carrie might have been planning the kidnapping for a long time, targeting Jenny as a means to gain access to the Irvines and Milo. Back at the Irvines' residence, Peter briefed Lia on the investigation, and Lia demanded to meet Jenny to grill her further about Carrie. They suspected Jenny might have been legally negligent in hiring Carrie.
Flashing back ten days before Milo's disappearance, Marissa and Jenny bonded over their struggles at the meet-and-greet parents' party. Jenny was saddened by Sarah's request for her to help with the fundraiser, which she found offensive given her already overwhelming household responsibilities. Her husband offered little assistance, expecting her to shoulder the burden of raising their son alone.
In the ladies' room, Marissa opened up about her struggles with her husband as they shared a glass of wine and laughed off their matching dresses. Marissa offered to take Sarah's pressure off Jenny's shoulders. As the police left, Richie warned Jenny to stay away from Marissa, fearing legal repercussions from the Irvines. He advised her not to apologize for anything.
At the Irvines' house, Detective Greco and Alcaras took over the case, informing them they had found Milo's tracker destroyed behind the school. The police worried time was running out with no contact from the kidnappers. Ana lied that she didn't know Carrie personally.
Marissa inquired what would happen if there was no contact from the kidnappers, causing Peter to break down in distress. Marissa rushed outside and collided with Jenny. A flash-forward scene revealed 27 days after Milo's kidnapping, where the detectives were surprised by recent developments in the case—one of their case board members had killed someone, ready to talk with her lawyer present, though the detectives didn't think it was appropriate to inquire about the kidnapping.
In the present moment, Jenny began to apologize, and the episode ended with the two women embracing, their story filled with emotion and unspoken promises for a better future.
