MISSING BOOK HELP

hey! so i saw a (ya?)book at barnes and noble a while ago and i was scrolling down the website today so i can find it. but i haven't been able to because i forgot the title and the author! HERE'S WHAT I REMEMBER FROM THE SYNOPSIS: its about a boy that goes missing and comes back years later and (i think) the siblings suspect something and i think it is revealed that the guy who came back isn't actually him at the end of the blurb! i think the title had something to do with the name of the missin ...more