Lucas Davenport and his daughter, Letty, team up to track down a dangerous scientist whose latest project could endanger the entire world, in this latest thriller from #1 New York Times bestselling author John Sandford. Gaia is dying . That, at least, is what Dr. Lionel Scott believes. A renowned expert in tropical and infectious diseases, Scott has witnessed the devastating impact of illness and turmoil at critical scale. Society as it exists is untenable, and the direct link to Earth's death spiral; population levels are out of control and people have allowed disarray and disorder to run rampant. While most are concerned about deadly disease, Scott knows that it is truly humanity itself that will destroy Gaia. It's only by removing the threat that the planet can continue to prosper, and luckily, Scott is just the right man for the job... When Scott then disappears without a trace, Letty Davenport is tasked with tracking down any and all leads. Scott's connections to sensitive research into virus and pathogen spread has multiple national and international organizations on high alert, and his shockingly high clearance levels at various institutions, including the Los Alamos National Laboratory, make him the last person they'd like to go missing. As the web around Scott becomes more tangled, Letty calls in her father, Lucas, help her lead a group of specialists to find Scott as soon as possible. But as Letty and Lucas begin to uncover startling and disturbing connections between Scott and Gaia conspiracists, their worst fears are confirmed, and it quickly becomes a race to find him before the virus he created becomes the perfect weapon.