"On the day Liz Emerson tries to die, they had reviewed Newton's laws of motion in physics class. Then, after school, she put them into practice by running her Mercedes off the road." Why did Liz Emerson decide that the world would be better off without her? Why did she give up? The nonlinear novel pieces together the short and devastating life of Meridian High's most popular junior girl. Mass, acceleration, momentum, force -- Liz didn't understand it in physics, and even as her Mercedes hurtles toward the tree, she doesn't understand it now. How do we impact one another? How do our actions reverberate? What does it mean to be a friend? To love someone? To be a daughter? Or a mother? Is life truly more than cause and effect?