In a unique episode, the path of a butterfly is the deciding factor in the fate of the young doctors. At the beginning, a butterfly landing on a woman's breast sets off a chain of events ultimately resulting in the death of J.D. and Turk's patient, leaving them to wonder what they could have done to change the outcome of their day. Taking a step back in time, the butterfly takes a slightly different path, landing instead on a man's chest setting in motion an alternate chain of events that leads our characters down a very different path. Will this be enough to change the fate of their patients?

original airdate--March 16,2004              songs

• "What a Wonderful World" by Joey Ramone
• "Theme Song: "Superman" by Lazlo Bane

Flashback--Dolls When Dr. Cox asks J.D. if this moment was always how he pictured it, he flashes back to playing with two homemade dolls of himself and Perry, and repeats the same question.