HBO’s “Lewis & Clark” miniseries is starting anew, entering a stage of major redevelopment with Michelle Ashford rewriting the six-part script, Variety has confirmed.

The troubled miniseries has already hit many bumps along the road, including production being shut down last summer after director and co-writer John Curran exited the high-profile project, which hails from producers Tom Hanks, Brad Pitt, Edward Norton and National Geographic Studios. Casey Affleck and Matthias Schoenaerts star as the titular 19th century explorers who went on a remarkable three-year journey to map the western United States.

“We have decided to redevelop this project with Michelle Ashford writing,” HBO said in a statement to Variety.

Ashford — who is creator and showrunner of Showtime’s “Masters of Sex” — was one of the three original scribes on the mini, along with Norton and the now-departed Curran. “Lewis & Clark” was greenlit last year at this time.

Affleck revealed the project’s behind-the-scenes turmoil in an interview with Collider last month, admitting, “The update is they are rewriting it, trying to make the scripts and the production a little bit more manageable. It was too unwieldy, they were trying to do so much, cover so many years, and it’s such a gigantic journey that it was almost impossible. It was a gigantic production that got lost control of and the seasons got ahead of them, and then they were finished. So now they’re sort of regrouping and aiming to just kind of start over again knowing what they know. It’ll be hard.”

With Ashford rewriting the entire project — which according to The Hollywood Reporter, already has multiple episodes in the can — HBO will have to greenlight “Lewis & Clark” for a second time, as the miniseries will be all but new. THR also reports that if the new version is not a go, the premium cabler will have to decide whether to use the previously-shot episodes, but recasting is potentially on the table. A new director was never appointed after Curran’s exit.

After being shut down in August, production was slated to start up again this spring. Now, the limited series’ future will depend on how Ashford’s rewrite is received.

“Lewis & Clark” is based on Stephen Ambrose’s 1997 book “Undaunted Courage: Meriwether Lewis, Thomas Jefferson, and the Opening of the American West.”