Dinosaurs, Siblings, Nature 

After their parents are lost in an accident, thirteen-year-old twins Grace and Marty are whisked away to live with their uncle Wolfe—an uncle that they didn’t even know they had! Intimidating Uncle Wolfe is an anthropologist who has dedicated his life to finding cryptids—mysterious creatures believed to be long extinct. Just as the twins and their uncle are getting to know one another, Wolfe finds out that his nemesis, Dr. Blakemoor, is headed to a Congolese jungle to poach a dinosaur and her clutch. Wolfe has to mobilize his team immediately if he wants to beat Blakemoor to the jungle. And his team does not include the twins. But Grace and Marty aren’t easily left behind. With breakneck daring, they literally drop into the Congo?falling from a helicopter. Through a series of perilous adventures, they eventually uncover longburied secrets about their identity and that of their uncle. Now, the twins must play a highstakes game, where the prize is a dinosaur egg, and the penalty, death. - from Amzon