Watch Online Free on Watchseries. When a couple decide to spend their summer vacation in a small town on the coast of Portugal, they had no idea that they would be faced with a dark mystery that would lead to seduction and betrayal. Mar is an erotic thriller set in the beautiful coastal town of Peniche Portugal. It's main characters Xavier and Eduardo visit a childhood friend Cristóvão (Diogo Tavares) who carries a dark secret that only his mother knows. Sexual tensions rise until the shocking secret is revealed but only after someone's fate is sealed.