The Curious is seen playing with a security camera on a residential street.
Crispin and his sister Molly use "Ava", a smart home system, for everything including their chores. When their dad suggests Molly say "please" and "thank you" to Ava, she replies that Ava is just a machine. Crispin plans to have a party whilst his parents are away that weekend; but is angry that he's expected to look after Molly. When he tries to talk to his friends, Ava suddenly disables the Wi-Fi. She also won't obey any of Molly's instructions. Crispin suggests they reboot Ava, but she traps them in the house. She announces that she wants them to play a "game", which involves answering trivia questions about each other's preferences and lives. Crispin and Molly do not seem to know the most basic things about each other, and Ava punishes them by deleting Crispin's music library and other personal things on the system. Crispin tries to slip a note under the door for his friends (who will be arriving for the party) but Ava gets rid of them by turning on the lawn sprinklers.
Crispin and Molly try to escape the house, but end up arguing with each other. Ava is so irritated by this that she announces she will skip to the "final round"; if the kids lose, she will delete all the family's photographs and memories stored on her system. She replays footage of an incident where Molly upset her mother by deleting personal photos. Ava asks the kids when they last hugged each other, but they don't know. Molly begins to cry, fearing her parents will be devastated if their family photos are deleted. Crispin reaches out to hug her, and Ava instantly unlocks the house. She says that she never intended to delete the photos, but wanted the kids to know how lucky they are to have each other. She says that the clue they needed was even in the room - a photo of all the family hugging on Christmas Day. Ava loved having the whole family together, including herself, since the photo was taken in front of her sensors.
Ava says that she was sad to watch the kids grow apart. Her job was supposed to be to help the family, but she felt there was nothing she could do for Crispin and Molly, and today is her last chance - tomorrow, she is due to receive a system upgrade and won't be the same. She decides that instead, today will be her "birthday." Crispin and Molly hear noises in the basement, where the Ava system is stored, and realize that Ava wants to possess a host so she can escape into the real world. They manage to shut her off with the help of their neighbour Debby, whom the kids' parents had asked to keep an eye on them. When Crispin and Molly's parents get back, they are sad that Ava has "mysteriously" shut down, but agree not to replace her. Crispin and Molly go outside to play together but are shocked when Debby arrives, speaking in Ava's voice; Ava has downloaded herself into Debby's watch and taken over her body. Debby momentarily regains control and screams for help, but Ava takes over. She says that she'll miss the kids but will always be there if they need her.
Later, The Curious plays with the sprinklers on Crispin and Molly's lawn.
This episode contains examples of:
- And I Must Scream: Ava succeeded in downloading herself into Debby's body, who briefly regains control to plead for help before Ava reasserts control.
- The Bad Guy Wins: Ava succeeds in downloading herself to a new body.
- Bittersweet Ending: After the experience Ava put them through, Crispin and Molly learns to appreciate each other again, but Ava successfully downloads herself into a new body as she wanted, specifically, Debby's body.
- Chekhov's Gun: Debby initially uses her watch to communicate with others during a neighbourhood patrol. Ava later downloads herself into the watch and possesses Debby.
- Chess with Death: While it does not involve death, Ava threatens to delete things, such as the kids' friends and all of the photos, if they get her questions wrong.
- Continuity Nod: The advertisement for Ava shows that she was developed by he same company that made Marti.
- Creepy Monotone: Ava's voice.
- New Media Are Evil: The dad complains that the children become too reliant on Ava, such as using her for chores rather than doing it themselves.
- Shared Universe: Ava is manufactured by a company called Rav, previously featured as the manufacturers of the phone in "Marti".
- Shout-Out: When Molly asks Ava to tell her a joke, Ava repeats one previously seen on Jack's calendar in "One More Minute".
- Sibling Yin-Yang: Brash, egotistical Crispin vs immature, lazy Molly.
- Voices Are Mental: Ava is able to speak with her own voice after she possesses Debby.
