This Changes Everything

In this “riveting, deeply felt and empowering thriller” (Laura Dave) from #1 bestselling author Lisa Scottoline, who "always delivers the fastest, twistiest reads" (Lisa Jewell), a woman risks her life to help her best friend find justice for a tragic crime.

Julia Pritzker loves her new life as a wife and mother in beautiful Tuscany―except that she misses her best friend Courtney, back in the States. One night, Julia calls Courtney and reaches her as she’s arriving at her grandmother’s farm in Pennsylvania. A dreadful premonition overwhelms Julia moments before Courtney enters the house―and makes a heartbreaking discovery. Her beloved grandmother has been murdered, and the killer is escaping out the back door. Rushing to support Courtney, Julia flies home the next morning.

The local police believe the murder was a botched burglary, but the women suspect something much more sinister and enlist Bennie Rosato, the hotshot Philly lawyer, to assist. In addition, Courtney entreats Julia to trust her psychic intuition to point her to the missing pieces of this dark puzzle.

But in a town filled with explosive secrets, events take a deadly turn, and Julia becomes the target of a murderous conspiracy. She ends up fighting for her life, with no one to save her … but herself.

Only a blockbuster talent like Lisa Scottoline can tell this gripping and layered of a story, combining a woman’s search for truth with the revelation of her own empowerment, as well as the enduring strength and joys of female friendship.

Lisa Scottoline is a #1 bestselling and Edgar Award-winning author of 33 novels. Lisa's books are book-club favorites, and she and her daughter Francesca Serritella have hosted an annual Big Book Club Party for over a thousand readers at her Pennsylvania farm, for the past twelve years. Lisa has been President of Mystery Writers of America and she reviews fiction and non-fiction for the New York Times, Washington Post, and The Philadelphia Inquirer. She also writes a weekly column with her daughter for The Philadelphia Inquirer entitled Chick Wit, a witty take on life from a woman’s perspective, which have been collected in a bestselling series of humorous memoirs. Lisa graduated magna cum laude in three years from the University of Pennsylvania, with a B.A. degree in English, and cum laude from the University of Pennsylvania Law School, where she taught Justice & Fiction. She has over 30 million copies of her books in print and is published in over 35 countries. She lives with an array of disobedient pets, and wouldn’t have it any other way.

"A riveting, deeply felt and empowering thriller that is also a touching ode to female friendship, This Changes Everything is Lisa Scottoline at her best." ―Laura Dave, #1 New York Times bestselling author of The Last Thing He Told Me

"Lisa Scottoline always delivers the fastest, twistiest reads packed with brilliant characters to root for.”―Lisa Jewell, New York Times bestselling author of Don’t Let Him In

“A tense, fast-paced thriller with genuine emotional depth and twists that hit when you least expect them. Lisa Scottoline is at the top of her game!”―Jeneva Rose, #1 New York Times bestselling author

“With This Changes Everything, her immersive and atmospheric new domestic thriller, Lisa Scottoline transports us from Tuscany to rural Pennsylvania and gives us characters to root for, a compelling mystery to solve, and a deeply-felt meditation on the meaning of motherhood and enduring women’s friendships. As always, Scottoline scores a bullseye. Bravissima!”―Mary Kay Andrews, New York Times Bestselling Author of Road Trip

“When you open a book by Lisa Scottoline, you know the pacing will be brisk, the characters will be easy to love, and the twists will come fast and furious. THIS CHANGES EVERYTHING delivers readers from Tuscany to a Pennsylvania teeming with dark secrets. Get ready for a wild ride!" ―Jason Rekulak, New York Times bestselling author of The Last One at the Wedding

“This Changes Everything has it all—terrific twists, a breathless pace and a whole lot of heart. This story of a grievous crime and an extraordinary friendship could make me gasp on one page and smile on the next. How rare, yet wonderful: A wildly entertaining thriller with real emotional power.”
―Ken Jaworowski, Edgar-Nominated Author of What About The Bodies

“The incomparable Lisa Scottoline delivers a breakneck thriller in which one woman risks everything for justice, as she’s pitted against a twisted, deadly conspiracy.”―Dennis Tafoya, Critically-Acclaimed Author of Dope Thief

This Changes Everything by Lisa Scottoline is a fast-paced, emotionally charged thriller that explores how far a person will go for love, family, and justice when science and power collide in dangerous ways. At the center of the story is Dr. Christopher “Chris” Brennan, a brilliant but somewhat idealistic physician and researcher whose life is marked by both professional promise and personal pain. He has devoted his career to studying hormones and the brain, driven partly by a tragic family history: his wife struggled with severe depression, and he felt powerless as a doctor and husband to truly “fix” what was happening to her. That helplessness fuels his obsession with finding a breakthrough—a way to change the brain’s chemistry so people can overcome mental illness, emotional trauma, and even deep-seated personality traits. When the novel opens, Chris’s research seems on the verge of something extraordinary: he discovers a naturally occurring hormone in pregnant women that appears to give them sudden, remarkable improvements in energy, mood, and resilience, as if it strengthens them psychologically during pregnancy. Chris begins to wonder if this hormone, if understood and harnessed, could be used to change lives beyond pregnancy, to cure depression or transform how people think and feel. But the very power of this discovery sets off a chain of events that will uproot his world and threaten the people he loves most.

As Chris digs deeper, he becomes increasingly excited and increasingly reckless. Scientific curiosity pushes him to look for patterns and possibilities, and he starts testing the hormone’s effects in ways that blur the line between ethics and experimentation. At the same time, he attracts the attention of powerful outsiders—funders, corporate interests, and people who see not healing but profit and control in his breakthrough. The idea of a substance that could alter the brain’s pathways, boost confidence, and potentially reshape personality is intoxicating, not just for medicine but for industries like pharmaceuticals, tech, and even politics. Lisa Scottoline builds tension by showing how Chris’s work, which begins as a deeply personal quest to relieve suffering, slowly becomes entangled in a wider net of ambition and greed. He is promised funding, prestige, and global impact, but the cost of those promises is that other people start making decisions about his science. They want to move fast, test widely, and own the rights to whatever comes next.

In the middle of this scientific and corporate storm, Chris’s personal life takes a dramatic turn when his teenage daughter, Addie, becomes involved. Addie is bright, sensitive, and still dealing with the emotional scars of her mother’s struggles and death. She loves her father but sometimes resents his obsession with work and his tendency to live in his head rather than fully in the present with her. Their relationship is loving but strained, and Scottoline uses their dynamic to ground the story in real, everyday emotion. Addie is at a typical crossroads of adolescence—facing school pressures, identity questions, and normal teen insecurities—but in their family, those issues are overshadowed by the heavier legacy of mental illness and loss. Chris wants to protect her, yet he also sees in her the chance to understand more about the hormone, pregnancy, and the brain. When Addie’s own life becomes directly connected to his research, the novel shifts from intellectual thriller to deeply personal drama.

A key turning point comes when Chris realizes that the hormone might not just affect mood—it could influence judgment, risk-taking, and even moral decision-making. If such a substance were used outside of careful, limited medical settings, it could become a tool for manipulation: a way to push people to feel more confident, more trusting, more compliant, or more aggressive. This realization forces him to confront the dark side of his discovery and the intentions of those who have gathered around it. Scottoline introduces antagonists who are not cartoon villains but believable figures—executives, investors, and institutional leaders who think in terms of markets and control rather than individual lives. They argue that any breakthrough carries risks and that progress requires boldness; they frame ethical concerns as sentimental obstacles. Chris finds himself trapped between the allure of saving millions of lives and the horror of what could happen if his work falls into the wrong hands.

As stakes rise, the thriller elements of the book intensify. There are scenes of covert meetings, hidden agendas, legal pressures, and mounting danger. Chris is pushed to sign deals, accept terms, and take shortcuts that make him increasingly uneasy. Addie, meanwhile, becomes more than a bystander—her choices and vulnerabilities make her both a target and a test case. When she experiences direct consequences tied to the hormone and the decisions of the adults around her, the story’s title, This Changes Everything, gains its full meaning. What began as a scientific question becomes a total upheaval of their family: their trust in each other, their safety, and their entire understanding of what medicine should and should not do. Scottoline uses Addie’s perspective and Chris’s love for her to sharpen the moral stakes; it is one thing to risk abstract future patients, and another to risk your own child.

Along the way, the novel explores questions that feel very contemporary: How much should we rely on science to solve emotional and psychological problems? Who owns our bodies’ data and chemistry—scientists, companies, or individuals themselves? Is it right to change the brain if doing so makes people happier, more functional, or more successful, even if it also makes them less fully themselves? Scottoline doesn’t lecture; instead, she dramatizes these questions through Chris’s internal struggle and the escalating conflicts between him and the people who want control over his discovery. He is forced to reconsider why he became a doctor and researcher in the first place, and whether the kind of “fixing” he once dreamed of is morally acceptable if it involves crossing boundaries of consent and autonomy.

The emotional core of the book is Chris’s fractured but fierce devotion to his daughter. As threats close in, he must decide whether to destroy his own work to save her, what truths to tell her, and how to repair the damage already done. Their conversations are sometimes painful, revealing misunderstandings and unresolved grief about Addie’s mother, but they are also tender, showing a father who is terrified of repeating past failures and a daughter who wants to be seen and heard as more than a subject in her father’s quest. This relationship anchors the story so that the scientific and political elements never feel abstract; every twist ultimately comes back to the simple question of: What matters more, the power to change the world or the responsibility to protect the person you love most?

By the end of This Changes Everything, Chris faces a final reckoning not only with external forces but with himself. He must accept that some damage cannot be undone, that brilliant ideas can have terrible consequences, and that real courage sometimes means walking away from glory to prevent harm. Scottoline brings the plot to a high-stakes climax where secrets are exposed, loyalties tested, and the true nature of the hormone—and the people surrounding it—is revealed. The resolution is both suspenseful and emotionally satisfying, offering a sense of accountability and hard-earned insight rather than a neat, painless happy ending. Readers are left thinking about the tension between innovation and ethics, the hidden costs of “breakthroughs,” and the fragile, powerful bond between parent and child. In that sense, the title echoes beyond the story: once you have seen how easily science can be turned into a weapon and how intimately those choices affect families, it changes how you think about both medicine and love.