She thought it was a “dream,” a chance to attend the prestigious Dalton School in Manhattan—which boasts a long list of famous alumni—free of charge. But the “once-in-a-lifetime opportunity” ultimately came with a terribly high cost, according to a lawsuit filed Thursday in New Jersey federal court.

The former Dalton student, identified in court documents as J.S., says she was sexually abused by an ex-headmaster, Gardner Dunnan, who allegedly used the “tremendous power, resources, and discretion that Dalton granted him as its long-time head of school” to prey on her.

J.S., who comes from “modest means,” says she lived at Dunnan’s home as a “family caretaker” while she attended the school on a full scholarship. She was just 14 years old when the alleged abuse began—and Dalton “turned a blind eye,” the court documents allege.

“Dunnan assaulted J.S. repeatedly, both in his apartment near Dalton and in his home in New Jersey, all while J.S. was entrusted to Defendants’ care,” the lawsuit states.

“In the course of these various assaults, Dunnan repeatedly touched J.S. without her consent, fondling her breasts, sticking his tongue in her mouth, disrobing and groping her, laying on top of her, and thrusting his genitals against her.”

Dalton “was aware or should have been aware” that Dunnan was “likely to engage in sexual misconduct or other harmful behavior,” according to the documents.

J.S., who is suing the headmaster and Dalton for unspecified damages, said she moved into Dunnan’s apartment in September 1986 at the headmaster’s suggestion. Dunnan said it would spare her the long commute to the elite prep school—which is on the Upper East Side—from her father’s apartment in Brooklyn, and save the family money, the documents state. She was “elated” by the chance to attend one of the top prep schools in the country—and live close to the headmaster.

At first, all was well, and she found Dunnan’s family “welcoming.”

“The Headmaster and his wife were kind to J.S. and generous with their time and money,” the lawsuit says. “They took her on outings and bought her a variety of clothes, including a winter coat.”

But that all changed when Dunnan sexually assaulted her for the first time, pulling her towel off and groping her body, according to the lawsuit, which details four instances of abuse between September 1986 and January 1987.

One time, she “awoke to find Dunnan lying on top of her, fondling her breasts,” and in another, he forcibly kissed her, “shoving his tongue down into her mouth,” the lawsuit says.

The abuse left her despondent and afraid to attend school, according to the papers.

“J.S. attempted to continue her studies at the Dalton School, but found herself unable to do so,” the court documents say. “She walked the halls feeling simultaneously disgusted and as if she herself had no value.”

The woman eventually transferred to a different high school. Meanwhile, Dunnan remained at Dalton until 1997, when he was forced to resign after it emerged that he’d had an affair with a married teacher, according to the documents.

J.S., who now lives in New Jersey, says she’s suffered “immense emotional pain and depression” since high school, but never revealed what had happened until recently, when several women accused President Donald Trump of sexual assault. After Harvey Weinstein’s swift fall from grace amid dozens of sexual assault allegations, she finally stopped blaming herself for what had happened, the lawsuit says.

“J.S. began to see that she was not alone, and that in fact, it might not be her fault after all,” the papers state.

A representative for Dalton said in a statement that the school “first received news of these allegations this morning.” “We take these issues very seriously and support any victim of sexual abuse,” the spokesperson added.

Dunnan could not be reached for comment.