The Missing Puzzle tells the story of Adriana, an ambitious and successful manager, working in a marketing agency, whose mental condition was destroyed by the tragic end of a relationship. The action of the novel begins when Adriana was brought there from a mental hospital. Adriana recalls her life, telling the reader what brought her to her present state.

After completing her undergraduate studies, she moves with her friends, where she finishes her master's studies, starts work and builds her career. At work she meets the mysterious, handsome Gabriel. The couple immediately like each other and, after time, they engage in a relationship full of love and passion. Adriana's life suddenly collapses.