The Key to Sector 5
After you get Cloud back in your party from his little ordeal in Mideel (click the link for more information) you have the option of revisiting Midgar to obtain some really nice items and weapons. All you’ll need to do is obtain the Key to Sector 5 in Bone Village. The key can be found in a number of locations, so dig around for a little bit until you find it.
Fly back to Midgar and enter through the previously locked gate.
As you’re walking past the church you should take a few seconds to take a look inside. Just as you enter you’ll see a quick flash of Aeris standing over the flowers in the middle of the church. Whether this is a split second game glitch or whether it was added purposefully to surprise unsuspecting gamers is not known, but this split second vision has fueled many rumors across the internet about possible methods of reviving Aeris and getting her back in your team.
After thousands of wasted hours by players around the world and after having the question posed to the developers of the game hundreds of times, it is pretty much an accepted fact: there is no way to revive Aeris and get her back in your team other than through using game altering codes (which have a habit of bugging out the game at various points).
Continue towards Wall Market and head into the little tent with the malfunctioning machine gun. Examine the front of the room to receive Tifa’s ultimate weapon: Premium Heart. The only other thing to do is make a quick stop by the weapon shop and talk to the guy who sold you the batteries. He’ll offer you a Sneak Glove at 129,000g which is a real sucker of a deal unless you have a lot of Gil lying around. On the other hand it is a pretty good item.