Gaspar's Hint: "In the Middle Ages, a woman's sheer determination brings a forest back to life..."
This is the one quest Gaspar mentions that isn't tied to a particular character, although special guest stars Lucca and Robo play a major role in this one. This is also the one quest which may be able to be performed without getting the Epoch, the only requirement is that you have visited Zeal Palace already in 12,000 B.C. and told the girl there to secretly plant the sapling. You can also speak to her at the commons in 12000 B.C. and speak to the enlightened one standing by an unplanted sapling. If you didn't talk to her before the destruction of Zeal she will ask you whether she should burn the sapling or plant it. Choose to plant the sapling. If you have already spoken to her in the past, she will say that "one Day the sapling could save the environment." If you tell her to secretly plant it, she'll keep the sapling after Zeal is destroyed, and Fiona will have it in 600 A.D.
Go to Fiona's villa in 600 A.D. and talk to Fiona and her husband Marco and you will learn that there is a desert to the south filled with monsters that are preventing them from replanting the forest. Head south to the "whirlpool." The monsters here are particularly weak against water/ice, so you may want to take at least one of Marle, Frog, or Magus to soften up your enemies to normal attacks.
If this is your first time through the game Magus will probably have more techs to learn than the rest of the party, so keep that in mind as well, equip a Gold Stud on whoever you want your main magic user to be. You'll fight a few enemies and pick up a few chests in the first room (Full Ether, a Lapis, an Elixir and an Aeon Suit). Travel down the stairs to the second room; the boss will constantly disappear and reappear, pick up the chests for an Aeon Helm, Memory Cap, and MuscleRing, Full Tonic, 5000 G, a HyperEther, and a Full Ether. Run into it whenever you're ready to fight. You can't leave his room once you enter, so not a good idea to just run in for the chests.
Make sure to pick up all the chests before you leave and grab a Power Tab in the left side of the first room after you beat the boss.
Unfortunately, if you check out the future just beating the monsters won't be enough to save the forest, there is centuries worth of work to be done. Luckily, you have a party member who wouldn't mind chilling out with humanity for 400 years. Talk to Fiona with Robo in your party and he'll agree to stay behind to help her replant the forest. Go to 1000 A.D. (Present), and you will see that the forest has been replanted. Save first, then put Lucca in your party and enter the shrine that stands where Fiona's house used to. Inside, the uppermost nun will sell you excellent helmets. At the top of the shrine you can find a very battered Robo.
Your party will end up around a campfire in the woods while Lucca repairs Robo. They will begin to discuss the reasons for them being able to go through time and Robo will bring up the possibility that the gates may not have been created by Lavos at all, but by an 'Entity' wishing them to witness everything they've seen. The times and places are very important to the existence of some entity, which may be reliving its past much like a creature flashing back over its life and thinking about what it could have changed.
Lucca will hint at a scene from her past she regretted, and after the party goes to sleep you will gain control of Lucca. Head to the right and you'll find a red time gate which will take you back 10 years to 990 A.D. to when Lucca's mother got into an accident which ruined her legs. Read the diary entry in Lucca's room, and the one in the back room of the house to learn that the password to the machine is Lucca's mother's name, or Lara. After Lara gets her skirt stuck in the machine, head southeast to the blinking dot and press , then press to finish reading the quest dialogue, and then press , then , then , and finally to spell out Lara (make sure you press the keys one after another and not all together). If you pull it off, congratulations, there will be a new diary entry, and Lara will be in good health from now on. Both when you visit the present and the ending scenes. If not, there will be a different diary entry and nothing will have changed in the present.
When you're willing to try again, keep loading your save file and keep trying until you get it right. To repeat it once more: After you reach "Type in password", press , then type "Lara" in a steady fast pace before her mother gets her legs shredded by the machine.
Robo will be waiting for you outside the portal and he will give you the GreenDream accessory, which allows it's wearer a one-time reanimation in battle, kind of like the Life3 spell in Final Fantasy VI or Link's fairies. You can also check the pedestal at the shrine to find the sapling you had the girl save thousands of years ago.