A suspicious House fire, an Amber alert during a carjacking and Fatal car crash caused by texting while driving introduce the members of LAPD Downtown, Station 77 and Trauma One.

The hunt for the shooter begins yielding unexpected results. Station 77 deal with a chemical fire, a heart attack on a bus and a scaffold rescue.

Stacey's abusive father appears out of nowhere. Sgt Mandell gets involved in an elder abuse situation and station 77 rescue a trapped hiker with a broken leg, attend a multiple vehicle freeway smash and rescue a young boy out of a drain.

A sniper is targeting Paramedics. Rescue 77 must still respond to 911 calls despite the additional risk.

The sniper situation continues but for rescue 77 it has to be business as usual.

A serial arsonist has chosen LA as his playing field stretching both station 77 and LAPD to the limit.

A car crash in the canyon starts a brush fire that soon becomes a real threat.

An infectious passenger on an incoming flight starts a search for others who might be spreading a highly infectious disease around Los Angeles.

A bank robbery downtown goes seriously wrong leaving one of the robbers and 2 of the hostages injured.

A port worker hears banging on a storage container and calls out Rescue 77 and Engine 77 to break in. Immigrants from the far east have been left to die in squalid conditions.

A school hiking trip goes seriously wrong leaving the children isolated with an injured teacher. Can the rescue services find them in time?

A gang lord brings his mercenary gang from Las Vegas to reclaim his territory in Los Angeles with murderous results.

As the war continues, Trauma One are hard pressed to keep up with the casualties and face a war of their own.