Nadia is heading to Ibiza to oversee the work at Sa Marea, the house she and her husband Marcos have bought. Her marriage is not at its best. Their inability to have children, which at first didn't affect their relationship, now seems to be all they can think about. The house renovations could be the chance for them to find some much-needed peace. But Marcos' lack of interest doesn't bring Nadia any solace and she finds herself drawn to the history of the house's last owner, Valerio Montalbán. From his diaries of the underwater archaeological explorations, Nadia deduces that the doctor discovered something important and that his death may not have been an accident, and she subsequently finds herself in the middle of a mysterious adventure.