The official summary of Crossed (Matched sequel): by Ally Condie

In search of a future that may not exist and faced

with the decision of who to share it with, Cassia

journeys to the Outer Provinces in pursuit of Ky—

taken by the Society to his certain death—only to

find that he has escaped, leaving a series of clues

in his wake.

Cassia's quest leads her to question much of what

she holds dear, even as she finds glimmers of a

different life across the border. But as Cassia nears

resolve and certainty about her future with Ky, an

invitation for rebellion, an unexpected betrayal, and

a surprise visit from Xander—who may hold the key

to the uprising and, still, to Cassia's heart—change

the game once again. Nothing is as expected on the

edge of Society, where crosses and double crosses

make the path more twisted than ever.

-Via Goodreads