The Bay Bridge joining Oakland and San Francisco made headlines in 2009 when it was shut down for a major renovation. To make the fix, Riley joins the engineering team tasked with cutting a football field-sized section of roadway from the bridge and replacing it - in just 72 hours! With traffic halted and the world watching, the team encounters some unexpected challenges. A crack puts the operation on hold and requires custom-made colossal steel brackets. The clock is ticking.