Zac Power Extreme Mission #2: Dark Tower

Book 2 in the interlinked Zac Power Extreme Mission Super Series! The second piece of IRIS is hidden in the crumbly ruins of a castle, surrounded by a dense, misty forest. Zac knew it would be treacherous, but he wasn't counting on the army of androids waiting for him . . . or having his nerdy brother Leon along on the mission!