Determined to help her amnesiac patients recover their lives, Boston psychiatrist Cristina Silva is achieving near-miraculous results by prescribing Recognate, a revolutionary new memory-recovery drug now in trials. She understands her patients' suffering better than most, because she's lost her memories, too. Desperate to become herself again, she pops the same experimental drug she prescribes to her patients. And, like them, she remembers a little more each day.

Until one of her patients, a successful accountant, jumps from an eight-story window to his death. And as Cristina's memories return, with them come violent visions and an incessant voice in her head. Maybe the drug isn't safe after all. But discontinuing it would mean forgetting everything she's recalled and losing herself.

Then an enigmatic, possibly dangerous man appears at Cristina's bus stop. He seems to know more about her life than she does and says she holds a secret that puts her life in danger. Perilously balanced between an unknown past and a terrifying future, if she wants to survive, Cristina must stay on the medication and unlock those memories before it's too late—even if the adverse effects of the drug could destroy her.