Warning: Major spoilers ahead

Detective Alcaras heads to the Irvines’ house, informing them that Carrie and Kyle had rented a house in the North Dunes, where Milo was believed to be with them. They had since left the property with the car they were using still there. While it appeared that Milo had been cared for with clothing and food, an adult male body has since been found in the lake, having suffered a gunshot wound to the back of the head They believe it to be Kyle.

Alcaras shows them a toy frog found at the scene, which Peter and Marissa identify as Milo’s toy, Mr Chips, but note that he didn’t take it to school that day as it had been missing since Easter – before they even hired a nanny. They realise that Carrie must have met and begun her interest in Milo before even working for Jenny.

They were on a family vacation at a ranch for the holidays when the toy went missing, and they’d searched for it for hours. They retrace their steps, noting groceries were delivered, they hadn’t left the house until after Mr Chips went missing, and no one else was at the ranch. If only the five of them were in the house, it theoretically means only one of them – Marissa, Peter, Lia, Brian or Colin – gave the toy to her.

All five insist they had never met Carrie before Milo went missing, so decide to go through that weekend with a fine-tooth comb together to see what’s been missed out from their memory. Peter shoots Lia a look that she catches, and asks what he’s inferring, and he responds that, as she had got out of rehab, perhaps she had arranged someone to drop off drugs to her. She tells him that she didn’t, but it’s clear he doesn’t believe her, prompting Colin to come to her defence.

Marissa instructs them to stop fighting, especially ahead of a camera crew arriving from Real Insight to interview them – something the others had forgotten about or weren’t aware of. Peter receives a text and disappears, which she notices, and then she realises that at some point that Saturday, Colin, Brian and Lia had gone out for the evening. Lia says she was supporting her friends at an art gallery opening but seems shifty.

The tense moment is interrupted with a knock at the door and a cake being delivered – a cake for Milo’s birthday which Marissa forgot to cancel. The arrival puts her into organiser mode, telling Peter to go and get upholstery cleaner so they can clean the couch. Sensing she needs some time alone, everyone else leaves. Marissa closes the lid for the cake, wishing her son a happy birthday, before calling the art gallery Lia claimed she went to.

Jenny drives over to Marissa’s house to go over questions for Real Insight, but gets a snarky phone call from Richie, who asks when she’s going to be home or if he’ll be “on duty again”. She asks him why he always needs to be free and talks about looking after their son like a job, and he responds by saying that he has always been like that and it was something she used to love about him. They both agree to try harder before she hangs up the phone.

With 90 minutes until the camera crew arrives, Marissa quickly gets Jenny up to date with what’s gone on, but wants to focus on the questions, knowing keeping herself busy will keep her mind off what’s happening. But that’s immediately ruined when the art gallery calls back, telling her they are open across the holidays from 10am to 2pm.

Knowing Lia, Brian and Colin left long after that, she heads to Brian’s studio to confront him and demands to know what they actually did. Brian shares they were quietly checking out an assisted living facility for him to potentially move into, as he wanted to have more independence. He didn’t tell them because he didn’t want to hurt Peter’s feelings, and it never came to be.

Brian also shares that Lia and Colin had only dropped him off there and picked him up, and he didn’t know what they did during that time.

Peter returns home to find Jenny stripping the covers off the couch, at the request of Marissa. She tells him that Marissa just wants to be kept busy, but he thinks it’ll just exhaust her more as she’s not been sleeping. Jenny apologises to him for her involvement in hiring Carrie, and therefore Milo’s disappearance, and he tells her that if he comes home, he’ll never be the same. So, while he’s trying to forgive her, he’s not there yet. He asks her to let him take care of Marissa, and Jenny leaves.

However, when Marissa finds out, she’s furious, saying she wanted Jenny with her and wanted to clean the couch herself. When she asks him his favourite thing about Milo, Peter admits he hadn’t read the interview questions yet but says he loves helping Milo get back to sleep when he’s had a nightmare.

Peter gets out of her hair and goes to see Brian, chastising him for not having food in his apartment and not eating properly. Taking over the kitchen, he says he’s going to fix something for him, checking the labels for soy (which he’s allergic to). Brian assures him he only ever buys food that he can eat too, so it’s safe.

As they sit down for soup, Peter notices Brian hasn't taken his pain meds. He says he hates them, as they make him ill and drowsy, and is considering just switching to a wheelchair, but Peter says no, and that they can do better. Peter questions how much a five-year-old is able to remember, and if Milo comes home how it will affect him. Brian notes that he only has flickers of memories – like getting out of his car and running to the front door, in the days before his accident.

Brian says Peter must have been scared when he saw the accident, but Peter says he wasn’t, because he didn’t realise how badly hurt he was at first but got scared when he didn’t get up from the floor. They reflect on the fun they were having playing, before he stopped looking where he was going to keep an eye on Lia, fell and changed his life forever, asking how it could have happened. Brian jokes he “wish he had a sexier answer” than tripping over his own feet, and Peter admits he was scared he was going to die, so wants him to live, urging him to take his pain meds. Brian reluctantly agrees and tells him he’s just had a refill. When Peter goes to get them, he sees there’s only three pills left in the bottle. Asking who picked them up for him, he says Lia did.

Colin pulls up outside the house and attempts to text someone again having heard nothing back. Marissa confronts him about the night Lia was supposedly at the art gallery, and when he lies, she calls him out for doing so. He finally buckles, confessing that he and Lia are secretly seeing each other, and they just went out to dinner for some alone together that night.

The conversation is overheard by Peter, who says while he doesn’t care they’re dating, he cares they’re both addicts. Colin argues they’re different addicts – he has a gambling problem, she takes pills – but Peter’s point remains, as it puts them both at risk for relapse, and believes Lia has already done so, with Brian’s painkiller stash depleted.

Colin flips, saying that Peter is obsessed with being the rescuer for everyone, and is tired of seeing him belittle Lia. He says he thrives off being needed, even if it's to the detriment of others. Peter says he’s been their caretaker since childhood as his parents never cared and he wanted to protect them from that. At some point his pretending to care became real. He was just doing the best he can for his family, and he’s worried about his sister.

Back at Brian’s apartment, he speaks to the neurosurgeon Peter met with several weeks prior. Brian asks that, while he’s not suitable for the experimental surgery he had spoken with Peter about, perhaps he could be kept on record for anything that may work in the future? The doctor, confused, asks Brian why he thought he wasn’t a fit – making it clear he had told Peter that he was.

Ten minutes before the camera crew are due to arrive, Brian, now drunk and in his wheelchair, heads over to the main house and angrily barges on their back door. When Peter opens, he rampages through the house, smashing things in his way, angrily berating Peter, Marissa and Colin. When Peter demands he leave, he tells him that “he knows” and will never do anything he says ever again.

Lia arrives back at the house, having driven to a pharmacy to get a drug test and prove that she’s still clean from pills, and finds the family in chaos. Peter tells Brian they “can’t do this right now” and still believes that Lia stole Brian’s drugs, but Marissa quashes that quickly by checking their medicine cabinet to find the full refill. Instead of apologising, he has little sympathy, asking who else was he meant to accuse, berating her again for her personality.

As Real Insight pulls up outside, Brian confesses he likes his wheelchair, and hates being forced by Peter to use a crutch, which leaves him in agony. He tells Peter to tell the truth to the group now, or he will. Marissa tries to get them to stop so they can focus on the interview, but Brian is insistent, so he confesses that he lied about Brian not being a candidate for spinal surgery.

When asked why, Peter says it’s because he knows Brian secretly loves being taken care of, and he doesn’t actually want independence. Lia asks what’s wrong with him, and he claims she’s the exact same way. He then readjusts, saying he was worried the surgery would go wrong and ‘if the edge of a coffee table left him with a disability, what could a botched surgery do?’

Something clicks with Brian, who comments that Peter shouldn’t know what he fell onto, and no one had ever mentioned the coffee table. Peter has maintained he was in the kitchen at the time, and Brian has no memory of what happened. Peter says he was told that, then says it’s a logical deduction, but Brian knows he’s lying and Lia realises as well.

Peter crumbles, admitting not only was he in the living room, but he caused the accident that’s been blamed on Lia all this time. He insists he never meant to hurt Brian, and just wanted to play with them, sticking his foot out for a joke, thinking the pillow fort they made would break his fall, with Lia taking the blame before he could. He insists he didn’t lie, just never corrected Lia, and he was only ten.

Lia, who has lived with that guilt her entire life, informs him he’s had decades to fix that mistake and tell her the truth, but he tells her it was “a gift” – the perfect excuse for her to be a “wreck her entire life”. She says he’s sick.

Marissa, struggling to stomach the conversation, begs them all to stop screaming at each other, but the siblings keep going, even when the doorbell goes outside and the camera crew awaits. She finally breaks down on the floor, sending Milo’s birthday cake flying, and the family realise they have taken things too far. Peter goes to comfort her, but she doesn’t want him near her, admitting that she’s happiest when he’s not around.

She then receives a phone call, informing her that there’s a boy that’s been dropped off at the police station – and it could be Milo.