In the summer of 1711, Seth, his father and his father's associate Julian were drinking in the Auld Shillelagh tavern in Alveston, where they intended to intoxicate a local girl named Rose so that Tom could sexually abuse her. However, the trio was stopped by Edward Kenway, a Welshman with whom the Cobleighs had a deep rivalry. The four briefly fought, with the Cobleighs gaining the upper hand, until they were interrupted by Caroline Scott, whose family employed Rose. The three men fled, but went to Edward's home two days later, slaughtering a pair of the family's sheep to provoke Edward.
The animosity between the two families rose over the next year, culminating in Tom, Julian and the Templar Wilson burning down the Kenway farmstead. Seeking revenge, Edward searched for the men in the Auld Shillelagh and arrived just before the Cobleighs and Julian reached the tavern. When they entered, Edward ran Julian through with a sword before chasing Tom and Seth outside. After a brief pursuit, Edward knocked Seth unconscious, unsure if Seth was one of the arsonists, and continued to chase Tom through the farmlands.