Humans

A couple buy a synthetic human, or `synth' to help around the house, but the new arrival threatens to expose their secrets. A retired engineer's paternal relationship with his own synth is threatened by a malfunction, an android and his owner go on the run, and a detective grows suspicious of his wife's close bond with her synth.

George's worst fears are realised when he is assigned a new Synth whom he cannot stand. Laura feels threatened by Anita's presence in her home, and Fred is held captive in Hobb's facility, which leads him to fear for the future of the human race. Karen and Pete have to hunt down Nisha after she escapes from the brothel, while Leo's search for information leads him down a dangerous path.

Laura is begrudgingly forced to keep Anita when she saves Toby from a road accident. George is planning an escape with Odi and Pete's hot temper earns him a suspension from work.

Laura insists the family take Anita for testing when Mattie tells her that she's seen Anita acting strangely, while Hobb is on Niska's trail

Killer Synth is the breaking news story, and public panic is growing. Karen is hot on Niska's tail, but are her motives for finding her more personal than professional?

Things are at the lowest possible ebb for the fractured Hawkins family. With Joe in exile and the kids tired of their parents' lies, Laura decides it's time to tell the truth.

Rejected and alone, Karen sets out to George's house to find Niska. Meanwhile Pete is determined to find out who Karen really is. The hunted Synths take refuge at the Hawkins.

With the Synths in captivity, the devastated Hawkins' realise how much Mia and her family mean to them and are determined to help them

Niska is living as a fugitive in Berlin, while the other Synths are laying low in the UK.

Laura must decide whether to accept Niska's request, while Karen and Pete learn about a special Synth being sold for unprecedented amounts on the black market. Hester uses questionable means to gain information from her prisoner, and Leo faces a new mission. Mia takes a risk to help Ed but is her secret now in jeopardy?

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.

Mia and Ed get closer but their relationship is thrown into jeopardy when their secret is discovered. Toby gets closer to Renie but offends her when he breaks through her synthie mask. Things look bleak for Niska until Laura brings in a surprise witness. When Milo confronts Athena about her secret agenda, she persuades him her research could be mutually beneficial. Karen and Pete delve deeper into the mysterious 'seraphim' investigation. As Hester's influence over Leo becomes clear, cracks appear between him and Max.

When Mia risks falling into the hands of a mysterious organisation, she is forced to take drastic action. Odi struggles to find meaning, while Sophie is awestruck by Renie's 'Synthie' lifestyle. As Pete recovers from his assault, Karen makes an admission that rocks their relationship. Hester and Leo stake out the Silo and track down the sniper who killed Ten. Hester agrees to deal with her peacefully, but can she be trusted? Mattie leaves home to reconnect with Leo.

Athena challenges Milo's ethics and is shocked when he reveals his real plan. Mia's surprise return has ramifications for the Hawkins family. Mattie finds Leo but can she trust him with her secret? Max resolves to begin a new community of Synths; when he learns how far Leo is prepared to go to complete his mission, he takes matters into his own hands.

When Mattie reveals that the Synths are planning to break into the Silo, Laura is determined to find Niska and ask for her help. Mattie asks Max to help save Leo from Hester's influence. Toby receives a disturbing message from Renie. Karen seeks out Athena's expertise and makes a life-altering decision. Mia and Hester break into the Silo, but things don't go according to plan.

In the aftermath of the Silo tragedy Karen feels she and Sam have no future and takes matters into her own hands. Niska and Astrid prepare to return to Berlin, but can Niska really walk away from her family? Joe leaves Laura shell-shocked with a frank admission. Hester seeks revenge and will stop at nothing to hurt Leo.

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.

Following a police raid at the Railyard, a grieving Max must deal with the fallout of his life or death decision, but have his actions caused irreparable damage to his leadership? Mattie stays by Leo's side, but his recovery takes a surprising turn. Rebel Synth Agnes begins a campaign against humans forcing Max into another difficult decision. Laura has her first meeting with the Dryden Commission and, realising she has a mountain to climb, she finds a possible ally in Dr Neil Sommer. She needs all the help she can get when she discovers a secret operation that could threaten Synth survival. And will Karen and Sam's cover be blown after Joe discovers their secret?

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.

Laura leads a tense Dryden Commission on a visit to the Railyard, but will Agnes' anger threaten its success? Mia comes face to face with Ed forcing her to confront her past, while an evening out for Karen, Sam and Joe turns to tragedy.

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.

Stanley and Anatole's true colours put Laura and her family directly in harm's way. With Mia speaking at the commission, Laura must do everything in her power to stop an awful attack. Leo and Mattie return to the Elster house where Leo comes to understand a painful truth, but Mattie has a secret that could knock their fledging relationship off course. Niska continues her mysterious journey that takes her to Wales, where she must defy all her instincts to survive.

Max must confront a friend turned foe. Laura reels from her heartbreaking decision, but when Mattie reveals her secret, she is spurred back into action. Niska's journey takes an unexpected turn, while Leo races to be by Max's side, but walks into danger.

Laura is in a race against time to stop Basswood. Her reputation is already on the line - but is she willing to give up her family and her freedom to save the Synths? Meanwhile, it looks as if Niska has reached her journey's end, while Mia, Leo and Max stand together in final battle, with seemingly little hope of making it out alive. And when the world learns of the atrocities that are taking place, will the fate of Synths change for ever?