Guardians Of The Galaxy Vol. 2L to R: Gamora (Zoe Saldana), Star-Lord/Peter Quill (Chris Pratt), Groot (Voiced by Vin Diesel), Drax (Dave Bautista), and Rocket (Voiced by Bradley Cooper)Ph: Film Frame©Marvel Studios 2017The fate of the universe rests on the "Guardians of the Galaxy" — the Marvel Cinematic Universe, that is.

Director James Gunn is working on the script for third movie in the "Guardians" franchise, following the successful release of "Vol. 2" in May. And in a Facebook Live Q&A, Gunn revealed that "Vol. 3" will play a key role in the future of the MCU.

"One of the things I'm doing with creating 'Guardians of the Galaxy Vol. 3' — it will take place after the next two 'Avengers' movies — and it will help to set up the next 10, 20 years of Marvel movies," he explained.

"It's going to really expand the cosmic universe. We're going to be setting up new characters."

Marvel has been saying for some time that the MCU will change significantly after "Avengers 4." The next phase will include "Spider-Man 2," but other than that, the studio hasn't announced any titles to avoid spoiling the events of the next two "Avengers" movies.

Even "Guardians" will see changes, even though it will help set the template for the next two decades of Marvel films.

Gunn teased that "Vol. 3" will "be the last movie of this version of Guardians of the Galaxy.