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 on the black market
Athena travels to the UK and her tragic secret is revealed. Niska's consciousness assessments begin, and the Synths are forced to leave their hideout.
Mia and Ed get closer but their relationship is jeopardised when their secret is discovered. Things look bleak for Niska until Laura brings in a surprise witness.
When Mia risks falling into the hands of a mysterious organisation, she is forced to take drastic action, while Sophie is awestruck by Renie's 'Synthie' lifestyle
Athena challenges Milo's ethics and is shocked when he reveals his plan, while Mia's return has ramifications for the Hawkins family
Mattie asks Max to help save Leo from Hester's influence. Toby receives a disturbing message from Renie, while Mia and Hester break into the Silo, but things don't go to plan.
In the aftermath of the Silo tragedy Karen takes matters into her own hands. Can Niska leave her family? Joe leaves Laura shell-shocked, while Hester seeks revenge on Leo.