Plumper's career began under Lieutenant William Frissell, who commissioned her in 1808 and commanded her during the British capture of Guadeloupe in January and February of 1810. That Caribbean campaign earned her crew a place in naval history -- in 1847, the Admiralty awarded the Naval General Service Medal with the clasp "Guadaloupe" to surviving participants, though by then most of Plumper's original crew were long dead. A false report in Lloyd's List in January 1811 claimed the brig had been lost in the St. Lawrence River while sailing from Halifax to Quebec. The rumor was premature by nearly two years.

When war broke out between Britain and the United States in 1812, Plumper found herself patrolling the Bay of Fundy under Lieutenant James Bray. The bay was thick with American privateers -- small, fast vessels that preyed on British merchant shipping. On July 16, 1812, Plumper and her consort captured the privateer schooner Fair Trader, armed with a single gun and crewed by twenty men. The next day she took the privateer Friendship, which carried just one gun and eight men. Working alongside HMS Indian, Plumper recaptured the merchant vessel Fanny, which had been seized by the American privateer Teazer while sailing from the Clyde to New Brunswick. In all, the two warships captured six American privateers during this period. On July 6, Plumper stopped the vessel Samuel, sailing from Oporto, confiscated $5,300 in cargo, and let her proceed to Boston.

On December 5, 1812, Plumper was sailing toward Halifax carrying a cargo far more valuable than any privateer's prize: tens of thousands of pounds sterling in gold and silver coin -- contemporary accounts differ on whether it was 36,000 or as much as 70,000 pounds -- destined as payroll for the British garrison. The Bay of Fundy in December is merciless -- frigid waters, fierce tides, and fog that swallows the coastline. Plumper struck the submerged ledges off Dipper Harbour and sank almost immediately. Roughly forty-five of the seventy-five souls aboard were lost, including Bray and every one of his officers. The brig went down so quickly that the treasure went with her. Mary Lane Bray, the lieutenant's widow, would later be recorded in Admiralty documents, the official confirmation that her husband had not survived.

HMS Bream and the sloop Brunswicker reached the wreck site the following day to search for survivors and attempt recovery. Some of the specie was recovered by British forces, but a good part of the cargo was lost. Local accounts of the gold recovery are numerous and varied, and precisely how much was brought up from the ledges has generated centuries of speculation. Lloyd's List reported the loss on January 8, 1813, in the matter-of-fact language of maritime insurance, but treasure hunters have read between those lines ever since. The cold, tidal waters of the Bay of Fundy are notoriously difficult for salvage work, and the ledges off Dipper Harbour scatter wreckage across a wide area. Whether the gold and silver still rests on the sea floor or was quietly recovered and never documented remains one of the Bay of Fundy's enduring mysteries.