A DIFFERENT DAWN

Nina Guerrera, the Warrior Girl of the FBI, is packed off with the rest of her unit to Phoenix to pursue a serial killer who evidently strikes once every four years.

Orthopedic surgeon Tom Doyle and his wife, ophthalmologist Meaghan Doyle, have been brutally murdered along with their infant daughter. What could the motive possibly be for a crime that’s clearly been planned down to the last detail? The Llorona case, which takes its name from the Latino tale of La Llorona, the weeping woman who seeks revenge on her unfaithful husband by killing their children and herself, swiftly balloons into something even more sinister when Nina’s team connects the crime to a remarkably similar series of triple fatalities—father, mother, baby daughter—that began 28 years ago in Phoenix before crisscrossing the country, every single one of them committed on Feb. 29. A data-driven search for clues identifies an obvious candidate for the role of the Leap Day killer, but when the team arrives to take him into custody, he’s been murdered too, apparently by someone whose slow-moving calendar has suddenly lurched into overdrive. As if these complications weren’t confounding enough, Nina, whose troubled early years already provided a pregnant backstory for her debut in The Cipher (2020), realizes that she has a much more personal connection to the Leap Day killer than she ever could have imagined.

A horrifying crime, cat-and-mouse detection, aha moments, and extended suspense, more or less in that order.