News of the `Killer Synth' finds its way into the media, causing widespread panic, and placing Karen under even more pressure to track down the alluring fugitive Niska. However, it seems there may be an ulterior motive to her hunt for the murderous synth. Meanwhile, the Hawkins debate whether to keep Anita in light of their recent discovery that she is not quite as `new' as she seemed, and while Joe worries his domestic synth might inadvertently reveal his secret, Mattie's decision to place her trust in Leo could put an end to the family's arguments.

The episode was rated 7.74 from 2493 votes.

Laura finds herself at odds with her family when she tries to return Anita to the shop, but Laura is begrudgingly forced to keep her when Anita saves Toby from a near-fatal road accident. Joe suggests that Laura is imagining Anita's strange behaviour, but he can't help noticing how human Anita appears when he has to check her for damage. George seems to have submitted to Vera's joyless routine, but he is actually hatching a daring plan to escape with Odi. Pete and Karen investigate a murder at a brothel, but after Pete's hot temper earns him a suspension, he finds himself stuck at home with Simon.

The episode was rated 7.72 from 2557 votes.

Laura is suspicious of Anita, and feels threatened by her presence. Hobb holds Fred prisoner in his facility, but while Hobb's superiors marvel at this unique specimen, Fred voices his fears about what this means to humanity. After a violent incident, Niska escapes her brothel prison, pursued by Karen and Pete. Leo's quest for information takes him to increasingly dangerous places. George's worst fears are realised when the health service give him a new Synth, Vera, who he immediately despises.

The episode was rated 7.71 from 2783 votes.

Niska is living as a fugitive in Berlin where an unexpected romantic encounter leads her to a huge decision with far reaching consequences. In the UK, Leo, Max and Mia are laying low in a coastal hideout while Mia works in a local cafe as 'Anita' to pay for their supplies and stay connected to the human world. Leo and Max come to the aid of Hester, a very special Synth, but when a mysterious organisation begins to pursue them, there's a tragic outcome. The Hawkins family are struggling to put past events behind them as they settle into a new home. In San Francisco, Athena Morrow, a fiercely-driven scientist researching AI is recruited by charismatic Milo Khoury, the entrepreneurial force behind tech company Qualia, for a top-secret project to create conscious Synths for the mass market.

The episode was rated 7.71 from 3141 votes.

While Sam reels from the events of Waltringham and Joe struggles to help him through it, truths are revealed and dangerous plans put into action at the Railyard.

The episode was rated 7.71 from 906 votes.

When fractures within the Synth community start to appear, all hope of stability comes under threat, and both families are brought back to fight for the Green-Eyes' survival.

The episode was rated 7.71 from 1143 votes.

Athena travels to the UK and her tragic secret is revealed. Niska's consciousness assessments begin. With more time at home Joe notices Sophie's increasingly eccentric behaviour. As Karen returns to work with Pete, cracks start appearing in their relationship. The Synths are forced to leave their hideout but Mia shocks them with a huge decision.

The episode was rated 7.69 from 2566 votes.

The Hawkins, a loving but troubled family decide to buy a 'Synth' called Anita, but they start to suspect there's something unusual about her...

The episode was rated 7.64 from 3377 votes.

A grieving Max must face the consequences of his painful decision. Laura discovers she's not being told everything at the Dryden Commission, while Joe uncovers Karen's shocking secret.

The episode was rated 7.62 from 1062 votes.

As Leo struggles to come to terms with being human, Mattie takes him back to the Hawkins' home, where a surprise night out allows them to confront their feelings for each other. Laura is determined to uncover the truth about the too-secret Operation Basswood and tries to enlist Dr Neil Sommer's help, only for things to take an unexpected turn. Joe reluctantly decides to help Karen with Sam, and Niska receives a mysterious message.

The episode was rated 7.61 from 972 votes.