Sword in the Stars

Know about the book -

Sword in the Stars is written by Cory McCarthy and published by Little, Brown Books for Young Readers. It's available with International Standard Book Number or ISBN identification 0316428833 (ISBN 10) and 9780316428835 (ISBN 13).

In this epic sequel to Once & Future, Ari and her Rainbow knights must pull off a Holy Grail heist thousands of years in the past -- without destroying their own destinies. Ari Helix may have won her battle against the tyrannical Mercer corporation, but the larger war has just begun. Ari and her cursed wizard Merlin must travel back in time to the unenlightened Middle Ages and steal the King Arthur's Grail -- the very definition of impossible. It's imperative that the time travelers not skew the timeline and alter the course of history. Coming face to face with the original Arthurian legend could produce a ripple effect that changes everything. Somehow Merlin forgot that the past can be even more dangerous than the future . . .