“The story you’re about to see is true — as far as I know,” says Laura Dern in a trailer for “The Tale.” Jennifer Fox’s film memoir centers on a filmmaker named Jennifer (Dern) who begins to come to terms with a relationship she had when she was 13 — or what she thought was a relationship.

Teenage Jenny (Isabelle Nélisse) becomes close with a married couple. Mrs. G (Elizabeth Debicki) teaches her equestrian and Bill (Jason Ritter) is her track coach. She’s happy with her arrangement with these “two very special people,” but the connection the trio share is obviously unhealthy. If everything was on the up and up, Mrs. G wouldn’t have to tell Jenny to keep it a secret.

Jennifer doesn’t pick up on anything sinister in her relationship with Mrs. G and Bill until her mother (Ellen Burstyn) finds a story she wrote about it as a kid. In fact, Jennifer confesses, “I only remember them. Why can’t I remember myself?” She soon realizes that the story she’s been telling herself since she was 13 might not actually be real. So she decides to delve into her past and find out the truth.

As Fox told us in an interview, “The Tale” is based on her own experiences. “It’s an exploration of memory,” she said, “how memory can be a ‘constructive activity’ that the mind engages to process trauma and to create our very identity.” She explained, “It’s my raw attempt to open up this often-misunderstood subject of sexual abuse in all of its difficult complexities, so we can begin to have a deeper conversation about how and why this happens.”

Dern won an Emmy and a Golden Globe for her supporting role in HBO’s “Big Little Lies,” which is currently filming its second season.

“The Tale” premieres on the premium cable network May 26. It made its debut at Sundance in January.