FX's American Crime Story: Katrina is getting a major overhaul.

Days after director Anthony Hemingway said the third season of the anthology was "stalled," showrunner Ryan Murphy has found new source material on which to base the series.

Katrina will now be based on Five Days at Memorial, by Pulitzer Prize winner Sheri Fink, after Murphy acquired rights to the book, The Hollywood Reporter has confirmed. Scott Rudin, who previously bought the rights to the book after its debut in 2013, is now attached to executive produce alongside Murphy, Nina Jacobson and Brad Simpson. Fink is also said to be involved.

That marks a change from the original vision for Katrina, which was to be based on Douglas Brinkley's book The Great Deluge. Katrina was poised to be the follow-up to Emmy darling The People v. O.J. Simpson: American Crime Story, but was pushed back in favor of The Assassination of Gianni Versace: American Crime Story due to what sources say were issues with finding the story as well as complicated water effects. Scheduling for the star-studded cast — including returning players Sarah Paulson, Cuba Gooding Jr. and Courtney B. Vance as well as franchise newbies Annette Bening, Matthew Broderick and Dennis Quaid — is also said to have been a factor in the delay.

With the new source material, Paulson will now take on the leading role. No other castmembers are currently attached to the retooled Katrina. Producers, however, are attempting to find new characters for several of Katrina’s key cast, including Quaid (who was to play President George W. Bush), Bening (as former Louisiana Gov. Kathleen Blanco) and Broderick (as former Federal Emergency Management Agency director Michael D. Brown).

Five Days at Memorial explores the aftermath of 2005's Hurricane Katrina at the New Orleans Memorial Medical Center as well as the decision by staff — including Dr. Anna Pou — to euthanize critically ill patients after being trapped in the hospital for days without power. The book explores the attempts to prosecute Pou and two nurses for homicide after an investigation revealed elevated levels of morphine and other drugs in 23 patients who died at the hospital. Fink won the Pulitzer for a story she did in 2009 for ProPublica and The New York Times Magazine.

Paulson will play Pou. A search is underway to find a writer and showrunner to pen the script for the series, which is slated to begin production in spring 2019.

The news comes two months after FX announced the order in the ACS seasons would flip. At the time, FX said that both installments would air in 2018. Then, on July 29, Hemingway revealed that Katrina had stalled. “Nothing has really been done,” he told THR. “We haven’t started prep on it at all.”

News of a season centered on Hurricane Katrina was first reported as part of a THR cover story in early 2016. “I want this show to be a socially conscious, socially aware examination of different types of crime around the world,” Murphy said at the time. “And in my opinion, Katrina was a fucking crime — a crime against a lot of people who didn’t have a strong voice, and we’re going to treat it as a crime. That’s what this show is all about.”

Versace, meanwhile, started production in April in Miami. The first nine minutes screened for reporters Wednesday at the Television Critics Association's summer press tour. The season, based on Maureen Orth's book Vulgar Favors: Andrew Cunanan, Gianni Versace and the Largest Failed Manhunt in U.S. History, will explore the July 1997 assassination of legendary designer Gianni Versace (played by Edgar Ramirez). His murderer, Andrew Cunanan (played by Darren Criss), committed suicide eight days later as Miami-Dade police were on the verge of capturing the serial killer behind five slayings. Oscar-winner Penelope Cruz stars as Donatella Versace, the sister of the slain fashion designer, who took over the company following his death.