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
: Cuddy pressures House to find a solution before Maya’s lungs fail completely. Meanwhile, House is distracted by Wilson, who has started "triplet-dating" (dating a woman who is also a triplet), leading to a series of pranks about identity and individuality. The "Eureka" Moment
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 Dr. House: 2Г—3
liver couldn't break down the heavy metals, leading to pulmonary edema. Lea's neurological system took the hit, causing seizures.
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. The title refers to a high-stakes medical mystery where Dr
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:
: 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. Meanwhile, House is distracted by Wilson, who has
The breakthrough comes when Chloe, the "healthy" one, finally collapses. House realizes the common denominator isn't what they are doing , but what they are taking . The Diagnosis: