39 clues. Doublecross

Siblings Dan and Amy Cahill have managed to avert one disaster recreation threatened by the man who calls himself the Outcast, but they have mere days to learn where the Outcast will strike next. The clues are pointing them toward a terrifying air disaster so they naturally think of the Hindenburg disaster, but how can that be the target when nobody in the present day travels by airship?.

Amy and Dan must find the Outcast before he causes a nuclear meltdown.

Siblings Dan and Amy Cahill have managed to avert one disaster recreation threatened by the man who calls himself the Outcast, but they have mere days to learn where the Outcast will strike next. The clues are pointing them toward a disaster modeled after Hurricane Katrina.

"Thirteen-year-old Dan Cahill and his older sister, Amy, are running out of time. An exiled Cahill known as the Outcast has already recreated three of history's worst disasters, and he's saved the worst for last. If Dan and Amy can't find and stop the Outcast fast, he will initiate a full-scale nuclear meltdown. But as Dan and Amy race around the world, they discover something horrifying. The Outcast's disasters are only a smokescreen to cover up his true plan, a diabolical revenge on the family that betrayed him. Soon Amy and Dan will have to confront a hard truth: Sometimes the only way to save the world is to sacrifice everything you love"--Back cover.

Siblings Dan and Amy Cahill have managed to avert one disaster recreation threatened by the man who calls himself the Outcast, but they have mere days to learn where the Outcast will strike next. The clues are pointing them toward a terrifying air disaster so they naturally think of the Hindenburg disaster, but how can that be the target when nobody in the present day travels by airship?.

Seventeen-year-old Ian Kabra, who is the head of the powerful Cahill family, is challenged by a Cahill from the past who calls himself the Outcast to stop him from recreating four of history's greatest disasters and hopes he can find Amy and Dan so they can help him decipher the hints in time to save innocent lives.