Helena and her twin sister Siri have long lived separate lives. Both are invited to an idyllic resort in the Italian alps, but as the reunion approaches it quickly turns out that Siri has her own agenda with her invitation.
Helena becomes painfully aware of Himmelsdalen's main activities. She desperately tries to prove her true identity, but the institution's staff dismiss her claims as another of Siri's manipulative tricks.
Doctors disagree on how to interpret "Siri's" sudden improvement in behavior. Helena realizes that she can take advantage of her fellow prisoners' fear of Siri and learns of a secret organization that can pave the way for a possible escape.
The doctors' actions suggest that they are starting to take Helena's story seriously, but in reality they are only looking to confirm their own treatment theories. Enzo comes to realize that Helena is telling the truth and helps her with her escape plan.
The young guide turns out to be anything but reliable, but Enzo remains confident. Helena receives valuable information about her sister during the sessions with Silva, and a new plan to prove her identity begins to take shape.
For the first time, Helena receives word from Siri, who apparently has no plans to return. The escape is imminent, but first another risky mission awaits, as Helena refuses to leave Himmelsdalen without having found the hammer.
Helena's newfound expectations are shattered when she hears news of her own death, but suddenly Margot emerges with a new spark of hope. At the same time, Redpath and Fischer are trying to uncover evidence in the hope of saving the facility's reputation.
Helena wins over Silva, but an accident happens when he tries to leave the facility. Now all that remains is for Helena and Enzo to carry out their escape attempt - and they are both prepared to do so at any cost.
