A hereditary condition affecting vision plays a central role, as the character Sara seemingly dies by suicide in her home’s basement, prompting her sister Julia (Belén Rueda) – who also suffers from permanent eye issues – to question the circumstances. Those around them are certain it was self-inflicted, but Julia isn't convinced and, when she and her husband Isaac (Lluís Homar) must reside in Sara’s house, she start…

The story centers on identical twins Julia and Sara (both portrayed by Belén Rueda), who are both battling a progressive eye condition that threatens their sight; Sara has already lost her vision completely, and Julia is facing the same fate. The narrative opens with Sara’s death, initially appearing to be a suicide after she was seemingly threatened in her home. However, details surrounding Sara's passing don't quit…