This case study introduces students to the structure and function of cellular organelles and seeks to show their importance by discussing diseases and disorders that can result when an organelle does not function as it should. The storyline follows a family whose joy at bringing home a new baby is soon altered by their child's sudden illness, which is eventually diagnosed as Leigh Disease. This disease occurs when defective mitochondria fail to produce energy needed by the cell, particularly affecting cells with high-energy needs like those in the brain, muscle, and gastrointestinal tract. The narrative also discusses some of the ways in which Leigh disease is inherited, treatment options, and the typical prognosis. The case was designed for an introductory non-majors biology course, but could also be used in other science or health related courses. Instructors also have the option of running the case in a "flipped classroom" in which students watch three recommended videos outside of class as a way of preparing for working on the case in class.