In the first episode of the series, the end of Sydney's Lockout Laws spells chaos for the Emergency Department. St Vincent's Hospital's Emergency Department is located in the heart of the city's bustling nightlife precinct. It's the first weekend in seven years that the strict drinking and nightclub laws designed to curb alcohol-related violence have been lifted. For Emergency nurses Darren, Yoon and Carly, that means a steady flow of drug-and-alcohol-affected patients are quickly filling the ward. An intoxicated man is brought in from Kings Cross bleeding from the head and Yoon is concerned he may have a brain injury. The youngest drug-affected patient of the night, an 18-year-old woman, is rushed in by ambulance, unconscious and showing signs of serotonin syndrome - a potentially fatal condition. A few floors up in theatre, perioperative nurse Nakita is scrubbed in for a complicated heart surgery for a 43-year-old patient, who is having a mitral valve replaced.