K-Pg

The end and a beginning. Alice Rosebine, chief Stone Splitter, has a plan. Send Tamsin Taylor back to the day a 10-mile wide asteroid strikes Earth. Force her, this most powerful of Piece Finders, to deflect it. For not only did this asteroid lead to the dinosaurs' extinction, it deposited large quantities of Hyperiontium on Earth, the cause, Rosebine believes, of all history's woes. Against her will Tamsin travels back via the Galapagos Islands, the Mayan city of Tikal, and Babylon....
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The end and a beginning. Alice Rosebine, chief Stone Splitter, has a plan. Send Tamsin Taylor back to the day a 10-mile wide asteroid strikes Earth. Force her, this most powerful of Piece Finders, to deflect it. For not only did this asteroid lead to the dinosaurs' extinction, it deposited large quantities of Hyperiontium on Earth, the cause, Rosebine believes, of all history's woes. Against her will Tamsin travels back via the Galapagos Islands, the Mayan city of Tikal, and Babylon. At each step she is doomed to die, only to re-appear in an earlier era.Tomas, the friend who protected her through previous adventures, fears that she will lose her mind. But Alejandro, the Chilean astronomer, has an idea - one which involves engineering a deception of awesome ambition.In K-Pg, Tamsin meets her final and largest challenge as a Piece Finder. When the fate of our planet rests in her hands, she must make a decision.