In 1713, Stewart attacked pirate captain Cliff and his crew in order to recover a map to an Isu vault in the Caribbean sea. Though Stewart had been tracked down by Edward Kenway and a few pirates aboard the Sea Dog's Bite who had been seeking the ship Cliff had stolen, he left his officers to take care of them while he left for the vault. Cliff's remaining crew counterattacked, bringing the fight to the Royal Navy's encampment, though Stewart managed to make his way deeper into the forest.
Kenway and his crewmates made their way through the Navy's defenses, until they arrived at the mouth of a cave bearing distinct Isu architecture in the form of an angled doorway. Inside the first chamber, they saw Captain Stewart and two redcoats inspecting the black and gold pillars that jutted up from the cavern floor. The pirates walked in, surprising Stewart. He claimed the vault as his own while the redcoats attacked the pirates. They were swiftly defeated, leaving Stewart alone and outnumbered. Before he could elaborate on the Vault's purpose or boast about how he intended to use it, Edward ran up from deeper within the Vault and plunged his Hidden Blade into Stewarts's neck, instantly killing him.