Age: 4th-middle school (disclaimer: there are a few death scenes)

"In a discontent kingdom, civil war is brewing. To unify the divided people, Conner, a nobleman of the court, devises a cunning plan to find an impersonator of the king's long-lost son and install him as a puppet prince. Four orphans are recruited to compete for the role, including a defiant boy named Sage. Sage knows that Conner's motives are more than questionable, yet his life balances on a sword's point -- he must be chosen to play the prince or he will certainly be killed. But Sage's rivals have their own agendas as well."

I totally wanted to slap the arrogant main character throughout the book

Spoiler

(although it was nice to see that his cockiness was complimentary to his hiding technique)

but the suspense and mystery is perfectly suitable for the age group. Although the setting is fantasy, the writing style focuses more on adventure and plot instead of setting and character. Also a complimentary tale to all the princess fantasy books out there.