Hurricane Katrina makes landfall in New Orleans. At Memorial Hospital, the doctors, nurses, and staff tend to patients and brace for the storm.

The staff and patients think they've made it through the worst - except the waters aren't receding. Reports of a new crisis circulate.

As the city floods, the hospital loses power. Mulderick and the staff attempt to cope with the terrible conditions and prepare for an evacuation.

Conditions continue to worsen. Mulderick, Pou, and more staff grapple with how to best help their patients - and how that help will be prioritized.

State investigators begin to explore what happened to the 45 people found dead at Memorial in the aftermath of the hurricane.

New evidence comes to light as Schafer and Rider dig deeper into their investigation of the deaths at Memorial.

Pou fights to defend herself. Schafer and Rider push their case forward.