In episode one, cameras follow two young men who are gunned down on Main Street in the close knit Charlestown neighborhood of Boston. After pushing through a crowd of onlookers, the EMS evacuates the two victims to Massachusetts General Hospital where top surgeons wage a heroic battle to save the life of a 17-year old boy. The case takes an unexpected twist that even doctors can't anticipate.

A horrific motorcycle accident involving an off-duty firefighter is caught on camera; a teenager falls through floorboards in a church; Boston Garden EMS personnel deal with a contentious sports fan; a volleyball player with a dislocated ankle.

A teen whose hand was severed in a car accident is taken to Massachusetts General Hospital to have it reattached; a firefighter falls from the roof of a burning building; a young man takes a bullet to the chest.

A car hits a medical student who is out biking; a woman with a latex allergy has a reaction after eating food prepared by workers wearing rubber gloves; an ER doctor keeps his cool when a patient becomes aggressive.

A man suffers internal injuries after a fall from a ladder; a woman is trapped underneath a subway; a man suffers a stab wound and refuses to be cut open.

Orthopedic doctors try to repair a rock climber's broken foot; a man wounded by a knife-wielding assailant is unexpectedly calm; a man trying to prevent his wife from falling down a flight of stairs ends up falling with her.