The library has been closed for half an hour already and Rosario, the librarian, is setting the last few books on the shelves and erasing the underlining that Armando, a waiter at the university's cafe, has scribbled in several novels. That is, until she discovers that they are not simple underlines and that they haven't in fact been written by Armando. The life of a young woman is in danger and now Rosario's is too. When she looks up, she finds Armando standing in front of her.