Quest giver: Katlyn (inside Madeleine's shop)
Pre-requisite: Complete the quest "Guard Duty
Note: Completing this quest will remove Madeleine from the game until the Post-Game
Inquire after Madeleine
Seek out Madeleine in Gran Soren
Talk to Katlyn in Madeleine's shop in Gran Soren's Venery. Next, head to the Arsmith's Alehouse and talk to both Arsmith and Nettie to get some clues about Madeleine's whereabouts. Head to the aqueduct and you'll see a cutscene showing Madeleine leaving through the eastern exit.
Follow her and exit Gran Soren. From the exit, continue to the right until you find her. Talk to her and you'll have the option to give the daggers to her or not. After making your choice, the guards will move in and she will hide. Ser Marcas will ask you about her; regardless of your answer, they'll leave you alone.
Madeleine will thank you and will ask for 50,000G in travel expenses. You can oblige to her request or decline. After that she'll leave and your quest will be complete.