Legend of a Forgotten Hero. Tales From Arcadia, #4

When Vortigern MacKay turned his back on his privileged upbringing he struggled to find a new role. Eventually he fetched up on the fringes of Arcadia in Seatown where he worked as a guard for Tegan Stuart, who was building a bridge over a stretch of deadly firewater. Tegan plans to reach Tuathal's Island and claim the treasure that is believed to be hidden there, but Vortigern uncovers a devious scheme to cross the firewater before him.
To defeat the conspiracy Vortigern must risk revealing his secret past, which will put him in even more danger from the many factions that are lining up against him.