Quest #102 Prat's the way to do it! - Alltrades Abbey
Quest Requirements: Perform a critical Pratfall twice
Quest Pre-Requirements: Level 40+ Minstrel and Side Quest #101 Complete
Reward: Minstrel's Manual and Gritty Ditty ability
This quest begins by speaking with the ghost in the Alltrades Abbey dining room on B1 of the town (screenshot below). In order to accept this quest you'll first need to have completed Side Quest #101 as well as have at least one person in your party who is a level Level 40+ Minstrel.
For this quest you need to perform a Pratfall ability in combat and score a critical hit with it - twice. As always for these sorts of quests I recommend you have at least two or three people in your party capable of performing this ability to speed things up significantly.
Return to the ghost after you've completed both critical Pratfalls then head to Stornway Castle. Go to B1 (go left when you enter and downstairs) you'll find some jail cells and in the southeastern most one (shown on my screenshot below) you'll want to speak with the prisoner.
Speak with him to complete the quest and acquire your reward.