: Kelly Severide learns he has a fractured vertebra but chooses to hide the severity of his injury and use painkillers to keep working.

In the Chicago Fire episode (Season 1, Episode 3), the "deep feature" is the introduction of Hank Voight . This episode serves as the origin point for the character who would eventually lead the spin-off series, Chicago P.D. .

: Casey refuses to be intimidated by Voight , officially filing the report and setting off a multi-episode rivalry that defined the show's first season.

: Despite the external threats from Voight , the crew of Firehouse 51 pools their money—originally intended for a new TV—to build a wheelchair ramp for the paralyzed victim.