While four friends are preparing to go to a party at Marta's house, the past seems to return and the events of that fateful day in 2004 are revealed. Namely, young Olga's world collapsed at the moment when her friends turned their backs on her and showed all their cruelty. As the present mixes with the past, Ana uncovers suspicious clues that lead to one of her friends and exposes her as Mato's mistress, leading to a dramatic confrontation.