Caught in a Web
Gia agrees to help you but requires a special potion vial.
Head over to the quest marker in the Farmlands. Just Fast Travel over there.
The cave is located to the west of the farmlands, at the end of a narrow valley.
Enter the Spider Cave and immediately, you can see a Blue Sack. a very helpful item(more storage).
Near the sack, you will find Griff's body.
And on his body, a note...
Read the note and see that Griff left a clue on where he stashed the vial.
The location hinted in the note is actually very close. Move to the right of the entrance a bit and count the egg sacks. You are looking for a blue egg sack surrounded by FIVE yellow egg sacks.
Inside the blue egg sack, you will find the Reinforced Potion Vial.
You can also grab Griff's Cleaver from the bottom egg sack.
Griff's cleaver however isn't so great.
Return to Gia so she can make the brew.
All that is left is to drink this brew.