Neuroscientist Evelyn Malcolm has built her life on reason: formulas, clean data, the illusion of control. But when the man she secretly loves turns up dead, everything implodes. She finds herself accused of his murder and interrogated alongside her estranged twin Vivian, a volatile mystery writer and wayward addict, whose matching DNA is found at the scene. But which sister committed the crime?
When the sisters are abducted and thrust into a kaleidoscopic world of psychedelic drugs, buried trauma, and whispered CIA experiments, Evelyn begins to doubt everything—her research, her memories, even her sanity. Haunted by what she can't remember and terrified of what she might, she's forced to reconcile with the sister she doesn't trust to clear her name and stop a looming catastrophe. As science and delusion blur, Evelyn faces a terrifying question: what if the real monster is the one wearing her face?
