The flapping of a butterfly divides Romina’s universe into two parallel possibilities: In the first one, she is abandoned by her biological mother, and then raised by another family with Germán as a brother. There, destiny causes them to build a relationship of love and tension in which they are forbidden for sexual desire. In the other possible world, Romina and Germán know each other as friends and their permitted but clumsy relationship will alternate this story with the other reality in a game of constant possibilities.