Bah.. ALL of you are wrong!
First, you must have the following, Underwater Materia, Final Limit Breaks for EVERYONE, EVERYONE's ultimate weapon, a Gold Chocobo, and two sets of Master Materia.
Got all of that? Then you either have no life or are a shameless cheater. Accept these facts and bow your head in silence, for the loss of any chance at a social life.
Done? Good. Now, go from Aeris' resting place back to Midgar on the back of your Golden Chocobo in less than five minutes. The game has a hidden timer, so you absolutely MUST do this in time! If you take longer, you have to start all over again. The good news is that for every minute you beat the clock by, you unlock a super weapon for one character. You can do this multiple times, but you only get the weapon after you revive Aeris. For you completionisdts out there, do it once for each character, than once more for Aeris... and one last time fvor the secret character you unlock when this is over.
That's right, a secret character.
Now, enter Midgar and make your way to the Church where you first met Aeris. If you made it under the clock, you should see a swirling blue portal in the middle of the flower field. Make sure you saved your game ahead of time, because there is no turning back once you step through.
Got it? Good. Now then, enter the portal, and you'll find yourself in a small area with a single lamppost, under which an old man is sleeping. He is called Gaspar, and he already knows why you are there! He says in order to gain an item to revive a lost one, you must go to the Palace of the Sun and defeat the guardian there. Only by doing so can you attain a Sun Stone, which has enough mgical energy to power an ancient device capable of transporting people into the Life Stream itself. For it is only there that you can find Aeris and return her back home.
But before all of that, you must defeat the Guardian in the back, for only he will allow you to access the portals you need to get out of this place. An FMV will then occur, wheer Cloud and the party carefully enter the back room, only to facefault as the feared Guardian is some pink looking stupid monster thing.
Don't let its looks fool you though! THis creature named Spekkio is very strong, and can only be harmed by magic!Upon defeating it, in which I highly suggest going all out with summons and massive amounts of your strongest spells, he will give you a 'Time Key', which allows you to enter those portals you saw outside. Apparantly, each one leads to a different time period. Since this is a completely different world, you cannot go back in time to save Aeris. Sorry.
From here on, you are told to go to 1000 AD and looks for a woman named Lucca. Not only does she have a time machine, but it flies AND she can take you right to the Sun Palace! Easy, right?
Problem... she's not home! Some problems have cropped up at the castle involving a couple of her friends. So, you must go through a forest, past some annoyingly weak monsters, and make your way to the castle. See that girl with glasses? That's Lucca... and apparantly she's in the middle of solving some form of marital problems between her best friend and his wife... who happen to be the next King and Queen of the kingdom your in. Somehow, the Princess had lost a very important item of sentimental value to the Prince, and until its found he won't speak to her. Lucca is on the scene, but she's only one person and the castle is huge! But hey! You want something, she wants something... all you need to do is find 'Crono's Sword' and Lucca will be grateful enough to fly you to your destination!
The sword is apparantly in the basement, past a contingent of monsters and traps. Apparantly, some punk blonde haired girl saw the gay looking rainbow katana and thought it'd be fun to play with. Sure, it looks sharp and deadly.. but RAINBOWS appear with every swing! What little girl wouldn't wanna play magical girl with it!? So, you give the kid a spanking, take the sword, give the kid to Barrett so he can cry at how much like his little Marlene she is, and make your way out... unfortunately, the little girl has a guardian in the form of a singing Robot called Gato. No, I don't know what Silver Points are, or why you get 15 of them for beating him, but you have to fight anyway. Careful, he's strong, and watch out for the boxing glove that pops out of his stomach!
After turning the thing into so much scrap, you get Gato's Head and Gato's Mike as key items. Return to Lucca and give her the kid, the sword, and the key items... as well as a million gil to not only appease her for man-handling her kid, but also for destroying her robot. Still, the Prince gets his sword back and forgives Marle with a smile, nod and tongue action... apparantly he doesn't talk.. at all.. but was withholding nookie from the Princess. Go figure.
Tell Lucca what you want, and she'll say that she already HAS the Sunstone. Well.. what's left of it at least. Still, there might be another one, so she agrees to take you to the Sun Palace. At this point, make sure your party can absorb fire damage, cause this next boss is a very strong elemental.
At the Sun Palace, enter and watch the FMV where a giant eye appears and becoems surrounded by flames. Here's where things get bad, because you can't target the eye.. you have to hit one of the flames, which will damage teh eye. Problem? After every successful hit, the flames shuffle. Magic HEALS the eye, so mass damage spells and summons are a nono. Limit Breaks are ok though, as long as it isn't fire-based damage.
So, after finally killing the damn thing, the eye actually turns to stone and reveals itself to be a Moon Stone. Lucca will geeks out about theories, before telling you that a Moon Stone is an unpowered Sun Stone. You have to let it absorb sunlight for over many many years.... but you don't have that kinda time!
Oh yeah.. time machine.. DUH! So, Lucca flies you over to a spot in the prehistoric ages (hey look, dinosaurs!) and sets it in some sunny spot that, from what she says, will last well into the far future. Now, its just a hop, skip and time jump away from picking up in said future, right?
Problem... when you arrive in a metropolitan future and land at the sunny spot, stone's gone. So, now you have to find out when in time is Carmen Sandiego... er... i mean.. when in time someone ganked your rock.
Go to the Middle Ages (for a time machine, it seems to only have several time periods keyed in... not really good for smaller jumps, is it?) and find that its still there! Go to the present time and, gasp! It's gone! So, you have to go find it...
Apparantly, according to a village nearby, some Mystic found it and took it back to his village. Mystics are intelligent monsters that have struck up a peace treaty with the humans. Weird, I know. Still, make your way to their village and find the mayor. Seems some rebel faction found the stone and are wanting to use its powers to take over the place. Hunt down the rebels (whose leader is named Ozzy of all things) and teach them why they shouldn't steal other people's shiny rocks! Take the rock back, lead the reberls to the town where they will stand trial, and get that rock back to the sunny place!
Cait Sith has an idea though, go back in time to whenever the current monarchy started and ask them to protect the place, make it into a preserve! Lucca seems to have ties to the royalty, so one jump back and a talk to the King and Queen, and they agree to mark that place off as forbidden/protected.
...Sure it might draw MORE theives, but at least the place will be guarded. Gotta feel sorry for the poor saps forced to protect the place though.
So, jump into the future and grab yourself a Sun Stone! Lucca will drop you back off at the End of Time and you can say goodbye to your chauffer. Gaspar, the old man, sees the stone, comments on it a bit, before pointing to a swirly green portal. Halfway there! You have to use the stone to power a device... so off you go!
...only to end up in some sort of underground city. Infested with monsters... very STRONG monsters... very BIG strong monsters... Oh look, there's a building with lights on! RUN!
By the time you make it inside, you either ran like a little b^tch, or you fought each and every time.. either way, you are either almost dead, or you cheated. Inside, a guy named Big Joe will ask if you wanna shop. Alot of the things he sells are for machines... and by the size of them, really BIG machines.
When you mention you have nothing to fit them into, Big Joe laughs and asks where your Gears are. Saying you have none makes the guy look at you as if you're crazy. From here, you get a tutorial on Gears and, by the grace of Deus Ex Machina, Big Joe happens to have a spare Gear for everyone to ride in to get out of the place. It won't last very long, being a piece of junk... but it will get everyong out of the ruins and into safer areas.
....Big Joe launches the Gear out of the building like a cannon in a very Evangelion fashion... conveniently forgetting that you are underground. As such, the junk machine craches through the roof of wherever you are and punches through until you see sky. At this point, though, the machine explodes, scattering you and your friends all over the place. Luckily, you still have teh Sun Stone.. unfortunately, now you have to find your friends.
Is reviving Aeris still worth it? If not, stop now, reset your game and go back to the previous save.... if so, continue.
Loser.. You have no life! All this for one girl? Geez... anyway, now you have to find your friends. Luckily, you landed near a village, where some guy named Citan is willing to take you to a place where you can not only get your own Gear, but where you can possibly get information on your friends. As such, he takes you to the Kingdom of Aveh, where his best friend is the crowned prince. His wife, a girl named Elly, tags along to keep her husband out of trouble. You get hook-ups all over the place, since apparantly Fei is some big-shot hero, and as such you get yourself a Gear, a map of the world, instructions on how to drive, and a Buster Sword sized to your Gear. Now, you can go onto your quest, especially since talking to trandom people in the Kingdom will net you some information... apparantly several things streaking through the sky landed in different places, which will be marked on your map for every one. When you have enough spaces to account for everyone in your party, that means you have a decent idea of where to go now.
The next part is redundant.. but go to each place on the map, fight a badguy and recover your friend. After each recovery, return to Aveh for an upgrade and to get your friend a nice shiny new Gear as well! Note, each person only gets a gear if you went through the five minute race for each person and beat it by at least a minute each time. That's right, that means you get to keep these suckers! Each person's Gear has similar weapons to the riders and upgrade accordingly. This means that Barrett's Gear will have either a big heavy weapon, or arm itself with a gatling gun of some kind. For the gears, you have to relead ammunition for Barrett and Vincent's Gears. When you have found everyone, return to Aveh and tell the crowned Prince, Bart, about your quest. He'll mention that OmniGears might have the power you seek. Perhaps if you talk to someone with alot of knowledge of Gear Mechanics and such, you can empower your gears to do what you need. You are pointed in the direction of the three sages, who helped make Fei's Gear.
One search later, you find a hut where the three Sages live... named Gaspar, Melchior and Balthazar. The old man Gaspar looks familiar... hmmm... anyway, you tell them what you plan to do and show them the Sun Stone. From it, they fashion several Solar Charges and install them, into the Gears. They become powered up and somehow gain golden armor peices and weapons. Don't ask, the Sages decided you needed to look particularly heroic. They say there is enough sun stone left to make a few more batteries, if you should need them.
Now, take your newly outfitted Gears and press all four shoulder buttons to activate the new Portal System.. which will jump you back to your own world. Fly your new Gears back to where Aeris died and open a new portal... this will send you straight into the realm of the Life Stream, where you have to fight a Bahamut-like creature in order to save Aeris. Careful, this thing drains your fuel with a few well placed techniques.. but if you outfitted your Gears at Big Joe's shop before hand, you should have no problem.
After smoking the Stream Entity, Cloud will leap out of his gear and swim towards Aeris, grabbing her into his arms in a cute FMV and carrying her back into his Gear. When the FMV is over, everyone is back at the Cetra Ruins where Aeris is awake and beating the shit out of Cloud for taking her away from the Stream. She activated Holy in time, but only just before you arrived. If you had coem sooner, the entire world would have been destroyed! Shame on you!
Well, she forgives you, and it now goes into a nice little FMV where an orgy between Cloud and the girls happen, while Barrett, Cait Sith, Red XIII, Cid and Vincent go off to get drunk. The scenes wil change between the orgy and the drunken party every so often... as in, before anything good happens.
Jump back to the world you got your Gears from after all of this and Aeris can get the strongest Gear in the game, which is labled El-Cetra. Also, you now get a new charcter... bring Aeris back to the Church you found her at, and you'll see a scene where a cloaked figure steps through, looking around curiously. Aeris will go up to the figure and it will remove its cloak, revealing itself to be a woman with long, sky blue hair who goes by the name of Schala. She will join your party, asking to find the way home to her little brother. You can also get her a Gear of her own, and all of her limit breaks are offensive magic. She uses staffs for weapons, just like Aeris, so you don't have to worry about anything weapon wise. Her Ultimate Weapon can be found in the world you got the Sun Stone from.
On a side note, you can add her to Cloud's harem quite easily.. just take her and Aeris to the Honey Bee Inn, where you got the Underwear for the 'Dress Like a Girl' sidequest, get a room... and the other two girls will join in.
Schala, apparantly, has a thing for leather and whips... and the girls happen to like the thought of a helpless Cloud. You do the math.
After this, you can go on with the game. Finally.
... Loser....