A gripping espionage and crime thriller by David Baldacci, first published in 2021. It is the fourth and final novel in the acclaimed Atlee Pine and brings FBI Special Agent Atlee Pine's lifelong search for her abducted twin sister to a dramatic conclusion.

For nearly thirty years, Atlee Pine has been haunted by the disappearance of her twin sister, Mercy, who was kidnapped from their bedroom when they were just six years old. The crime shattered her family, left Atlee physically and emotionally scarred, and ultimately inspired her to become an FBI agent.

Following the revelations in Daylight, Atlee and her trusted assistant Carol Blum finally have proof that Mercy survived her abduction and escaped her captors years earlier. Determined to reunite with her sister, Atlee embarks on her most dangerous investigation yet, uncovering decades of lies, abuse, revenge, and hidden identities. As she closes in on the truth, powerful enemies emerge, forcing her into a life-or-death confrontation that tests her courage, loyalty, and resilience.

Unlike the earlier books, which combine standalone investigations with the overarching mystery, Mercy focuses almost entirely on resolving the central mystery surrounding Atlee's family. Baldacci balances emotional revelations with relentless action, delivering explosive confrontations, clever twists, and a satisfying conclusion to one of his most compelling series.