Netflix just dropped a trailer ahead of the four-part project's release ... sharing scenes of Biles' life with husband Jonathan Owens, her desire to return to competition, and her training leading up to the Paris Games.

While there is much excitement for Biles' return to the Olympics, the show will also focus on one of her biggest stories -- her withdrawal from competing for gold to address her mental health.

In a brief portion of the trailer, a scene features Biles talking on her phone and saying, "So, having these mental blocks in the gym recently."

Biles was then shown struggling to do her routine -- which is very out of character for her --then walking off the floor with the announcer confirming her exit from the competition.

The clip then cuts to Biles wiping away tears.

Biles has been vocal about her battle with the "twisties" -- a term familiar to gymnasts to describe a mental block that affects their performance -- and how they played into her experience in Tokyo.

"It's honestly petrifying trying to do a skill but not having your mind & body in sync," Biles said during an Instagram Q&A at the time. "Literally can not tell up from down. It's the craziest feeling ever. Not having an inch of control over your body."

While Biles did have support ... she also received plenty of criticism -- the trailer also highlighted a tweet calling her "quitter of the year."