The watch first appeared when Artie explored MacPherson's room in the Personnel Quarters Archive. Artie searched his room hoping to find an answer to why he was seeing what appeared to be MacPherson's ghost haunting the Warehouse. He found the pocket watch in a drawer, along with a letter from MacPherson saying that the watch should be his and that he might need it someday.During the conflict between the Warehouse and Walter Sykes, Artie once again visited MacPherson's room, where he again found the pocketwatch; this time he took the artifact with him. The pocket watch was later revealed to be an artifact created to lead to a failsafe artifact for the Warehouse in the case that it was destroyed.
The watch appeared as a golden pocket watch with "Barbossa" written on the face. The watch had a loose back panel which reveals that several black diamonds embedded in its workings, hinting how to reach the failsafe. The failsafe was guarded by descendents of the Knights Templer, a group called the Brotherhood of the Black Diamond. They were instructed to protect the failsafe, Ferdinand Magellan's Astrolabe, at all costs. They know about the Warehouse, but they believe Ferdinand Magellan's Astrolabe is better kept with them. On its back the watch had the words "Carregar o Botão" Portuguese for "push the button".
After stealing the Astrolabe from the Brotherhood, the Warehouse agents knew that ML had to stand for Magellan—Barbossa was captain of a ship, the Victoria, that went with Magellan on his expedition. Magellan was also married to Barbossa's daughter. The astrolabe was missing a piece and wouldn't activate. When the watch came in contact with the astrolabe, it turned back into a watch with the time being 4:18. The Agents didn't know what that meant, until Pete thought it could mean military time 16:18 - as in New Testement Mathew 16:18--"And I tell you that you are Peter, and on this rock I will build my church, and the gates of Hell will not overcome it." Furthermore, the cornerstone of St. Peter's Basilica was laid 1506 April 18—therefore, the astrolabe's missing piece must be at the Vatican. After the agents realized this, the watch turned back into its previous form, a 24-hour stop watch, and continued counting down.
The watch was activated when the button on top was pushed and after the Warehouse was destroyed. When activated, the watch glowed and turned into a 24-hour stop watch and begins counting down. However, it didn't start at 24 hours; it started at however long it has been since the Warehouse was destroyed. For example, if the Warehouse was destroyed an hour ago the watch would start counting down at 23 hours. If the fail safe isn't acquired by the time the watch counts down, the fail safe won't work.