When his wife leaves him, taking their daughter with her, Andres, a burned-out, demoralized middle school physics teacher, takes solace by forming a bond with Hector, a troubled but promising student beguiled by the physics of roller coasters. Under Andres' guidance, Hector is soon staying after school every day to work on a project for the county science fair competition. When Hector's family discovers that he has quit his job, however, the boy stops coming to school. Soon, Andres is embroiled in a conflict with Hector's uncle, who is visiting from out of town. Uncle Lorenzo insists that Hector's drug-addicted mother can't hold a job and that Hector must support the family. When Andres refuses to back down, escalating the conflict, Lorenzo complains to the school, and Andres is put on leave. Meanwhile, after Lorenzo finally leaves for home, Child Protective Services whisks Hector and his siblings away. When Hector calls Andres and asks if he will take him in, Andres—with difficulty—says no. But he contacts Lorenzo, who decides to take in the family. Months later, at a science fair, Hector—with a new teacher—welcomes Andres—with his reunited family—as Andres watches his former student present his project.