Margherita Mazzucco in My Brilliant Friend. Photo: Eduardo Castaldo/HBO

Spoilers below for My Brilliant Friend.

Life under the Ischian sun gets considerably darker for Elena Greco in the latest episode of HBO’s My Brilliant Friend. During her Mediterranean summer vacation, the teenage girl’s days are initially filled with beach idylls and writing unanswered letters to Lila Cerullo (Gaia Girace), as well as a reunion with her longtime crush, Nino Sarratore (Francesco Serpico). The two bond over Dostoevsky and Maupassant, and they even share a kiss. But where Nino’s late-night trip to the kitchen as Elena (Margherita Mazzucco) feigns sleep results in the boy sweetly tucking her in, a subsequent visit by his poet father Donato (Emanuele Valenti) is pure predation.

After imploring Elena not to leave the island, Donato jams his tongue into the chaste girl’s mouth, slowly moving his hand up her leg and under her nightgown as she lies there impassively and starts to cry. It’s a gut-wrenching scene to watch, and Elena’s molestation at the hands of Donato ultimately hastens her departure and leaves her utterly confused. “However unlikely it may seem today,” an adult Elena says in voice-over, “as long as I could remember, until that night I had never given myself pleasure. I didn’t know about it, to feel it surprised me.”

My Brilliant Friend star Mazzucco and Girace were plucked from obscurity to portray the show’s leading roles, which makes Mazzucco’s poignant performance in this disturbing scene all the more impressive. Since it was shot before HBO’s announcement that they’ll now have an “intimacy coordinator” on set for sensitive scenes, Vulture checked in with series’ director Saverio Costanzo via email (translated into Italian, then back into English) to learn how he shot such a disquieting moment.

Costanzo said Mazzucco needed no extra preparation before filming on a closed set. “From the first rehearsals on, Margherita was aware of how important [it] was,” he explained of the scene, which employed a body double for all of the hands-on moments. “[So] I didn’t have to explain or talk about this with her.” As for Mazzucco’s co-star, Constanzo said Valenti is “a very sweet and loving man” who did his best to put the actress at ease.

Saying he “felt such a sense of horror” about Donato’s actions, Costanzo added that he “didn’t want the scene to be realistic and therefore intolerable to the viewer. We decided to use a soft piano tune in contrast with the violence to allow Elena’s surprise to emerge in addition to her horror.”

After the last take, the director said he congratulated his young star on her performance. “She had impressed us. She was still very excited, and would say, Poor Elena, poor Elena. I believe that on that day Margherita truly met Elena and became an actress.”