The House of the Scorpion
by Nancy Farmer
Esperanza Mendoza is Senator Mendoza's ex-wife and the mother of Emilia and María. She abandons her family, and for two years, María is led to believe that her mother is dead. Of course she isn't dead – just on a mission. A winner of the Nobel Peace Prize, her goal in life is to take down Opium and expose El Patrón's evil system to the world.
As a vocal crusader for good, Esperanza definitely has a lot in common with her daughter María. She's so committed and passionate that she can be overbearing and even obnoxious (also like María). Matt finds Esperanza off-putting when he first begins reading her book, A History of Opium, but that's because he doesn't fully understand the truth of it. When he meets her, he knows she had been right all along. Esperanza is the one who gives Matt the plan to save Opium. In fact, without her influence, our hero might never have returned to save the day.