Background
Upon entering the City of Amaranthine for the first time the city guard will approach you and want to search your bags for smuggled goods, for which they are quickly scolded by their commander in defense of the Warden. The city is having trouble with smugglers and thieves who have all but taken over the city. You will be approached by Constable Aidan who will tell you that if you have time the city guards could use your help with a particular problem.
There are two distinct paths you can take with this quest line, you can help the smugglers or you can help the city guards. If you choose to side with the smugglers you get an extra person to fight at Vigil's Keep for you, but the guards will call you a murderer and treat you rudely. Choosing the smugglers is the only way to get a key into the guard house in Amaranthine. Note that doing a SINGLE quest, even the bartender quest for the smugglers, will prevent you from EVER siding with the guards. Similarly, after starting Law and Order, you will turn all the smugglers hostile, essentially preventing you from ever siding with the smugglers.
After speaking to the constable you will find out that trade has almost come to a crawl, that smugglers have moved in selling stolen goods at exorbitant prices. If you decide to help and shut down their operation they could take the goods you find and distribute them to the needy.
Walkthrough
Speak with Constable Aidan after the gate guard cutscene to initiate the quest. Aidan will direct you to a "Suspicious Character" in the market place next to Glassric the Weaponsmith. Engage this NPC, who will then lead you in a clockwise chase around Amaranthine through 5 groups of "Hired Goons" that ends on the western part of town just outside the walls. You can take your time to clear them out as the "Suspicious Character" will wait for you by each consecutive group. After the last group, your quest will update. Go back and speak to Aidan to initiate the last part of the quest.
Speaking to Aidan will spawn a "Shady Character" outside the abandoned house where the chase ended. The "Shady Character" will then drop a key that you can use on the trapdoor in the house to get to Smuggler's Cove, the final area of the quest. Finish off the "Smuggler Leader" and the remaining smugglers, and return to Aidan to complete the quest.
Result
Nathaniel approves (+1), Sigrun approves (+1), Justice approves (+1) (after reporting the secret door)
The Smuggler Leader's chest contains various gems and gold, Trickster's Gloves & Feet of the Nimble
The Smuggler Leader can have one of Gloves of Guile, Antivan Leather Boots, Spear-Thrower, The Felon's Coat or The Rose's Thorn as random loot; possibly the only means of obtaining some of these items without an import in DAA.
10 
and Nathaniel approves (+2), Sigrun approves (+2), Justice approves (+2) (after killing the Smugglers' Leader)
Bugs
- If you complete this quest while having Smuggler's Run in your quest log, you can still have the Bartender at The Crown and Lion open the hidden passageway - with the proper disapproval from the city guard.
- If you have both Smuggler's Run and Law and Order in your quest log, and you enter The Crown and Lion while still in the process of killing the groups of "Hired Goons", and then you ask the Bartender to open the hidden passageway, then both quests will be marked completed with disapproval from both the city guard as well as the smugglers. You can enter the hidden passageway, and if you finish killing the "Hired Goons" a quest marker will show up on Constable Aidan, but he refuses to speak with you.
- WARNING! If you start Law and Order and its counterpart quest (by either speaking to Constable Aidan or Shady Character), you will NOT be able to initiate Sigrun's Roguish Past. Initiate Sigrun's quest first before starting either of the smuggler's quest.
- After completing the quest, it is possible to gain unlimited gold and experience. After completing the quest, talk to him for your 'donation' of fifteen gold. He will ask you to kill the liuetenant, decline, this will exit the conversation. Talk to him again, and he will give you another donation and experience. This can be done as many times as wanted; although if anything else is done, such as opening the chest on the other side of the room, you will no longer be able to speak with him.
- If you go to the smuggler's cove first, before you encounter the Shady Character in the marketplace, you can kill the smuggler leader then. This however prevents you from completing the quest because when you encounter the Shady Chracter he will lead you to that building and you can't kill the leader again.