The episode opens with three identical 19-year-old sisters—Maya, Lea, and Chloe—admitted to Princeton-Plainsboro. They were performing a synchronized gymnastics routine when Maya went into respiratory failure, Lea suffered a seizure, and Chloe remained perfectly fine—until she began experiencing "sympathetic" pain so intense it mimicked a heart attack. The Investigation
House orders an aggressive chelation therapy tailored to each sister's specific organ failure. As they recover, the sisters realize that their drive for "identical perfection" nearly killed them. The episode ends with House alone in his office, spinning a juggling ball—reflecting on how even "identical" things are never truly the same. Dr. House: 2Г—3
House discovers that the sisters were all taking a specific "natural" performance-enhancing supplement to stay thin for gymnastics. Because of a rare phenomenon in female development (skewed X-inactivation), each sister's body processed the supplement's toxins differently: As they recover, the sisters realize that their
The title refers to a high-stakes medical mystery where Dr. Gregory House must solve a case involving a set of triplets whose identical DNA makes diagnosing their divergent symptoms a nightmare . The Case of the Mirror Triplets Because of a rare phenomenon in female development
had a delayed reaction that eventually triggered a cytokine storm. The Resolution
: House treats them as a single organism with three different "outputs." He theorizes that while their DNA is the same, their epigenetics —how those genes are expressed—have diverged due to secret lifestyle differences.