House observes the sisters in their shared room. He notices that while they look identical, Maya (the one with lung failure) has a slightly different callus on her finger. He realizes she isn't just a gymnast; she’s a secret smoker. But that doesn't explain Lea's seizures.
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 observes the sisters in their shared room
: 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. But that doesn't explain Lea's seizures
: 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