It's the week of Mardi Gras and it's the busiest time of year for our first responders. Working the parade route comes with its own challenges and unique cases. Keeley treats a man who impaled his hand on a fence. While Titus and Dan have to navigate through a flood of people to treat a man stabbed in the face. But most drama happens off the parade route. Titus and Dan race to save an 18-year old shot in the head through and through. Randy & his partner Devin, search for suspects in an armed robbery, which leads to a high-speed chase.

Swat officers J. and Alley come face-to-face with the violence in the city after a high-speed chase turns into a shootout with their suspect. The violence takes a bizarre turn when Keeley gets called to a woman whose eyeball has been bitten out in a fight. Titus and Dan head to one of the most dangerous projects in the city in order to treat a shooting victim. Towards the end of the shift, Keeley joins Holly and Nick as they try to piece together what happened between two Spanish-speaking men involved in a bloody knife fight.

The city is in mourning after a well-loved Police officer is shot and killed on duty. Vic and P chase a suspect following an altercation with another officer. The dangers of the job become even more real when Vic and P are called to assist other officers who were shot at by a suspect while serving a warrant. Titus and Dan deal with a resisting patient who takes a swing at Titus. Holly and Nick treat a woman whose leg is mangled in a bicycle accident.

Titus and Dan treat a woman who was viciously stabbed in the face, and Holly and Nick tend to an emotional young transgendered woman who was assaulted. A wild police chase ends with a major car accident, and the firefighters of SQURT 16 race to put out a structure fire. Throughout the long night the character of New Orleans' residents shines through in dramatic and quirky ways.

On the fourth of July in New Orleans, the heat seems to trigger havoc in the streets. Holly, Nick, and Keeley arrive at a bloody scene where a woman could lose her arm after a bar fight. Then at the scene of a car accident, a first responder is assaulted while trying to tend to the victims. And as fireworks explode across the city, police officers Randy and Devin catch a teenage bike thief, and offer some tough love to get his life on track.

On the Nightwatch, you can't save everyone--but you try. New partners Tommy and Arkady join a desperate search for a victim who went under in the river; Holly and Nick rush a motorcyclist with devastating injuries to the hospital; Titus and Dan assist a pedicab driver with a nasty leg injury; and Randy and Devin search for a drug dealer hiding in a dangerous neighborhood.

For the men and women on the Nightwatch, two things never stop: the calls and the questions. How can someone shoot an eight-year-old boy? How do you stop the drug epidemic in the worst parts of New Orleans? How do you get guns off the city streets? As the first responders do everything they can do save the victims of several shootings, a drug overdose, and more; and the police officers chase suspects who end up having illegal firearms, they find themselves asking these questions--and only wishing they had the answers.

The best people on the job never stop looking for ways to do more and be better. For police officer Justin, the objective is joining the force's SWAT team, and he takes a big step by leading a raid with the SWAT officers. Meanwhile, the first responders deal with a rash of scary calls, including a man suffering from amnesia after getting hit by a car, and a woman who fell off a roof. And after a man survives a suicide attempt, Arkady forges a bond with him by sharing the story of her mother's own suicide.

Like any dad, Titus wants the best for his son. As an EMT, he sees just how dire life can get. From drug addicts desperate to kick their problems, to assault victims, to a teenager who drove his car into a tree, nights in New Orleans reveal the struggles of life in this city. Meanwhile, police officers continue to work desperately to get guns off the street--and make the city a safer place to live.

On the 10th anniversary of Hurricane Katrina, the emergency responders reflect upon this natural disaster. Calls include a house fire, a SWAT assault, a moving car hit by a huge falling tree, a stabbing victim, and much more.