Complex sentence: A street fair is interrupted by an attack serving as a distraction for the villain's forces to attack the keep of the local baron, allowing the player characters to begin to discover the secret alliances trying to take over the town.
Split into simpler sentences: A street fair is interrupted by an attack, which serves as a distraction for the villain's forces to attack the keep of the local baron. This provides an entry point for the player characters into the main quest to discover the secret alliances trying to take over the town.