Peacock's mystery thriller All Her Fault delves into a thrilling case that begins when Marissa Irvine's young son goes missing from his first playdate. As the story unfolds, it unravels several mysteries, and it leaves the audience with questions regarding motherhood and the lies we tell to protect our families and the ugly consequences.Jake Lacy plays one of the most complex characters of the series. He plays the role of Peter Irvine, Marissa's husband. Initially, he's portrayed as a father whose world turns upside down when his young son goes missing. By the finale episode, we come to learn about his truth, and karma hits back sooner than expected. Throughout the story, the entire blame is pinned on Marissa, and she often has bouts of anxiety attacks, but it turns out that it wasn't Marissa but Peter's fault. Mothers are an easy target to blame when something goes wrong with a child, but this series breaks the notion and shows how a father's action in the past can be responsible too. Speaking to The Hollywood Reporter, Jake Lacy revealed how he prepped for the role,"I had to find my way into that and then stick to those guns even as the rest of those characters and potentially some viewers don't agree with some choices he's made."Lacy is known for his nice guy roles (Obvious Child, The Office, and How To Be Single), but his role as a central antagonist in All Her Fault was truly fascinating. Even though it was not his first time delving into darker roles, Lacy played Peter Irvine with utmost dedication. Most of the viewers couldn't guess that he was the bad guy until the season finale.How did Jake Lacy try to legitimize Peter Irvine's choices in All Her Fault? View this post on Instagram Instagram PostIt's never easy to play a complex character as layered as Peter from All Her Fault, let alone justify his choices. Yes, Peter was a protective father and husband, but that doesn't excuse the choices he makes or the lengths he goes to cover up his crimes. Lacy says that in order to legitimize Peter's character, one needs to analyze him well. He further tells The Hollywood Reporter,"I think Peter is, at the end of the day, petrified, filled with fear and self-loathing, and any of these things that poke at his fallibility or his weaknesses are unbearable for him, and that’s hardwired in."He continues,"That’s a little door into not being in judgment of these things Peter has done. The difference between going, ‘Oh, that’s messed up,’ and, ‘You’re a monster.'”Thus, the only way to anchor Peter was to approach him without judgment, to look at the fear and self-preservation sitting under every bad choice he makes.What did Peter Irvine do, and what happened to him at the end of All Her Fault?In the finale episode of All Her Fault, the authorities manage to trace back Milo's whereabouts to Carrie Finch, Jenny's nanny. Turns out she took Milo from his school. Peter rescues Milo from a motel and gives the bag full of cash to Rob, Carrie's father. He then kills Rob with a lamp and leaves the motel with his young son and dropping him off at the police station. Why? Here's the twist.Realizing that Milo is gone, Carrie rushes to the Irvines with a gun, and even though she misfires and kills Colin, she makes it clear that she's there only to reveal the truth. She then reveals her real identity is Josephine Murphy and recounts how six years ago she was in a terrible car accident with Peter and Marissa, which killed her newborn. But turns out, that the baby who died wasn't hers but that of Marissa and Peter's.After the fatal accident, Peter switched their baby with Josephine's, and that's Milo's real identity. During a scuffle with Carrie, they accidentally kill her. But Pete tries to manipulate Marissa by assuring her that whatever he did was for their good. Marissa doesn't turn him in to the police, but karma hits back. During Colin's service, Marissa kisses Peter, but he goes into shock. He's allergic to soy, and Marissa had consumed it. As Peter tries to reach for his EpiPen, he finds it missing from the kit and dies. We get a small sneak peek into how Marissa had previously taken out his EpiPen and exchanged it with an expired one. Watch All Her Fault on Peacock.Also read: Is All Her Fault a limited series? Here’s what we know about the future of the Peacock thrillerFollow Soap Central for more such updates.