This Hunt becomes available immediately after you complete the Rogue Tomato Hunt at the beginning of the game (in Rabanastre). It can be completed with just Vaan in your party but is significantly easier to complete once you reach the Nomad Village in the Giza Plains and Penelo joins your party.
It is also recommended that your party be around level 3 or 4 minimum before engaging in the fight. You should take some time to clear away as many of the surrounding Wolves as you can in order to make the fight as easy as possible.
The petitioner for this Hunt is Gatsly. He is also located in the Sandsea Tavern within Rabanastre sitting on the ground to the right of the Notice Board.
Thextera is in the Dalmasca Westersand which can be reached by exiting Rabanastre using the Westgate. Hug the cliff on the left side of the road around to reach the Galtea Downs area as shown in the map below.
Level: 6
HP: 380
Steal: 
Pebble, 
Potion, Wolf Pelt
Once again, make sure to clear the area of as many of the patrolling Wolves as possible. The easiest way to lose this fight is to lose control by having to face additional monsters in the area.
Thextera will also cry for help in an attempt to enlist any nearby Wolves to join in the fight. Attack any additional Wolves as they appear and then take town Thextera. Head to the Nalbina Fortress to purchase items, Magick, weapons and armor or take some time to level your characters if you are having trouble with this fight.
A video of the battle in the Zodiac Age version is included below:
Return to Gatsly once Thextera has been defeated. Rewards include: 500 gil, 
Headguard and a Teleport Stone.
