With a deep dive into her subconscious, Jessica Biel starred in and executive-produced he Sinner. It was the most exhausting experience of her career, she says, and also the most fulfilling.

In usa’s the sinner, Jessica Biel single-handedly gives new meaning to the phrase “it’s no day at the beach” when, as ostensibly happy mom Cora Tannetti, she suddenly rises from her towel in a rage and viciously stabs a sunbathing stranger to death. that jaw-dropping bit of carnage prompts a labyrinthine search of the story’s other crime scene Cora’s psyche for the cause of her snap.

Petra Hammesfahr’s 1999 novel e Sinner was a smash hit in her native Germany, with an English translation released in 2007. Knocked out by the book’s psychological intrigue, Biel bought the rights and produced this eight-episode series under her production shingle, Iron Ocean. he Golden Globe-nominated performance marked Biel’s first regular series role since her six seasons on he WB’s anodyne family drama 7th Heaven.

Playing Cora a dramatic swerve into pitch-dark, almost Hitchcockian territory could bedevil the most seasoned actor. “It was absolutely the most complex, exhausting, draining experience of my professional career,” she says. “At the same time, it was the most satisfying and fulfilling creative experience.”

It was draining because Cora, who lands in police custody in a near-catatonic state, is initially as perplexed as her interrogators as to the “why” of her crime; her self-investigation parallels theirs. Biel portrays a woman who’s a prisoner of the past in more ways than one, straining to recollect the events of that fateful lakeside day while trying to understand long-buried childhood memories that slowly surface.

Biel says she prepared for the role by researching “the psychology of trauma patients, people with PTSD, people with traumas who don’t remember things and so create stories to fill in the blanks.” She lucked out with showrunner Derek Simonds, who’s studied the psychology of dreams; they play a big part in the unfolding of Cora’s story. “I did some dream work with him, really diving in to the subconscious,” she says. “hat was my way in.

“It was this puzzle of a performance,” Biel says. “We wanted to take you down the path of ‘Wow, this woman is one thing,’ and then, ‘Wait a minute she’s totally something else.’ And then, ‘What she doesn’t remember?!’

“Every day was a question mark can I pull this off?” she recalls. “Will I be able to hit the nuances and find the complexities of this scene? How can we, and the audience, follow this unreliable narrator and be empathetic toward her?”

With the residents and law-enforcement community of Cora’s upstate New York town united against her, she finds empathy in detective Harry Ambrose (Bill Pullman), who, we learn, is similarly burdened by past trauma. heir deeply etched shame and guilt provide the glue for a potentially redemptive bond.

“By the end of the story,” Biel says, “Cora’s gotten to a place where she can begin to heal from her damage, but Harry hasn’t even begun to scratch the surface.”

With that in mind, she reveals that the second season (due in August) will focus on Harry’s journey. Biel will not continue her role as Cora, though she will continue as an executive producer. “We have to be really careful,” she says of the upcoming storyline. “It can’t be goofy.” Now, that would be traumatic.