When a shady connection from Sully's past leads to a clue about the whereabouts of Excalibur, the famous sword from Arthurian legend, Nathan, Elena, and Chloe join Sully in a race to find the priceless relic. A race that has far greater implications than any of them realize. They are not alone, however. Pursued by a vicious “collector” with unclear motivations, the team must work together to stay one step ahead of certain death. What they eventually discover on a treacherous island lost to time, is far more startling than they ever could have imagined.