Hogwarts Legacy offers a massive open world to explore, full of collectibles, side quests, and fantastic beasts for the player to find and capture. While these beasts provide their own side content, they often interact with other people in the world, leading to unique side quests of other characters dealing with beasts in different situations as the player.
Hogwarts Legacy also gives players the ability to wait on the world map to forward time from either night to day or day to night. While this may seem purely for the aesthetic of a day-night cycle, there are many things to be done exclusively during the night, much like this quest.
Beginning A Thief In The Night
This quest is given to the player by a merchant in Irondale, in the eastern section of the Feldcroft Region. While walking through town, you'll hear Padraic Haggarty, a stall owner, complaining that his stall is being robbed each night. Recently, the thief stole many galleons along with a family Heirloom and requests the player find and track down the thief, who he claims to be his sister. To find the thief, you'll first have to check back at the stall at night. You can either come back the next night or open your map and use the wait option to make it nighttime. To track the thief, you'll need to follow the trail of galleons they dropped when running off with the loot.
Finding The Thief
Starting at the stall, cast Revelio to highlight the dropped galleons along the ground. Continue in the direction of the dropped galleons, picking them up on the way if you wish while constantly casting Revelio to highlight the next galleons. It is wise to leave the Galleons and collect them on the way back, as losing this path of dropped coins can become incredibly difficult to find again. While Revelio highlights the next two with each cast, you may sometimes lose your way and the trail, with no marker or icon directing you where to go next. Should you get lost at any point, you can refer to the image above and head straight to the end location of the thief.
You'll eventually reach the end of the path and find the stash of items and galleons and the thief, a Niffler. Finding the thief is part of the quest, and it is possible to complete the quest without the Heirloom but with fewer rewards. The Heirloom is actually located on top of the small alcove and is easily spotted after heading above. After collecting the Heirloom and finding the thief, return to Mr. Haggarty and complete the mission. Should you complete the mission without the Heirloom and go back and get it, you're unable to give it to Mr. Haggarty and won't receive total rewards for this quest.