NOTE: This will contain answers to Riddles, you've been warned.
Head to the church and you'll be presented with a Riddle. The answer is Organ so scan the organ at the back of the room. Head to the Court House and back to where Two-Face was. Take out the thugs there and you will be presented with a number puzzle. You must line up the numbers so the bottom number is 275 and the right number is 325.
After this, you'll be given a word puzzle. The answer, is secret. He will then reveal the next location. Head to the building marked and by the street at the bottom of the building you will see a wall with a question mark on it. Examine the wall and you'll punch through it. Go through the door and listen to the Riddler talk. Turn around and on the wall there will be a question mark. Throw a baterang at the dot of the question mark to unlock the next door. In the next room, you can use the line launcher to get to the safe tile across the room or you can throw baterangs at the different question mark switches around the room to reveal a path. Either way, once you get to the other side, use a baterang on the switch to your left (as you look toward the entrance) to raise the platform. Glide down to the hostage and rescue him.
At this point, if you haven't found enough trophies and riddles, you won't find out the next hostage location. Keep finding statues and solving riddles until you are informed that you can use the Enigma Machine. Open it and the solution to the riddle is "darkness."
Head toward the way point and check the back of the building for another false wall. It will have a question mark on it. Walk up to it and inspect it to break through. Inside, jump down onto the button to start a shell game. Don't bother keeping track of the shells. Flip on detective mode to see where he actually ends up. The second hostage will be under the left shell. Time to collect more secrets.
