Make sure you have 1000 gold before speaking to Madeline in the Inn!!!!!!!
This is a muti-part quest, first escort Madeleine from the inn in Cassardis to the Encampment, after she talks to you, give her the 1000 gold she asks for.
The next side mission you need is called Chasing Shadows. This quest becomes available after completing the main quest Lure of the Abyss. Speak to Mason to begin the quest. After it is done, you MAY need to leave and re-enter Gran Soren to speak with Madeleine again to unlock the achievement.....