In Brighter Shores, the Brannof family needs your help recovering a lost shipment of weapons. This guide details how to complete "The Lost Shipment" quest.
Starting the Quest:

Find Brannof Hall's dining room (near Brannof Boulevard, accessible from the Town Square). Speak with Cohen; he'll reveal the missing weapons and give you two leads (be sure to talk to him twice to get both).
Completing the Quest:
You'll need to investigate two separate leads. Remove any Town Guard gear before questioning anyone.
Lead 1: Captain Shirker:

Find Captain Shirker on his ship, The Vincible (southeast area of town). After a meal at The Delectable Dab (near Town Square), he'll mention a man in a blue waistcoat.

Locate the Man in a Blue Waistcoat in the Town Square. He'll direct you to "The Illusion," a weapons dealer. To get the weapons, you must impersonate someone named Sam (who has a monobrow).

Visit the hairdresser on Old Street West (8 Silver and 280 Copper for the monobrow).
Lead 2: The Hooked Hand:

Speak to patrons at The Hooked Hand (near Eel Street). They'll point you to The Frequently Fresh Fish Stall.

The Fishmonger needs a Fetid Flounder (requires Level 25 Fishing). Write a note (using Quill, Ink, and Paper from Lord Brannof's desk), hide it in the fish, and give it to the Fishmonger.

Hide and watch; a Furtive Stranger will buy the fish.

Follow him to Monab Row. Remove your Guard armor to reveal your monobrow, identify yourself as Sam, defeat the thief (Level 30), and retrieve the Plumbatae.
Return the weapons to Brannof Hall to complete the quest.