Traumatized by the loss of her partner, Helena (Hel) Brant is hiding out from life, working night-shifts at an anonymous call center in a provincial Swedish town. When her long-estranged twin sister Siri reaches out to ask if she would visit her in the Italian Alps, Hel impulsively takes this opportunity to escape her greyed-out life - hesitantly hopeful that she may even be able to rebuild some of the bridges that have been burned between her and her unreliable twin. At first sight, Himmelstal looks like a luxurious sanatorium and picturesque alpine hamlet but Helena soon realizes that it is in fact a secure facility and that her twin sister has another agenda with her visit. Siri proposes a 24-hour swap so she can visit her lover in Milan. Helena refuses Siri's plan, but wakes to discover that Siri has done it anyway.