Complex sentence: Their conversation is interrupted when Simon is kidnapped by vampires, leading to a confrontation in a nearby hotel, in which the group is nearly killed before werewolves (that share a truce with the Shadowhunters) intervene and rescue them.
Split into simpler sentences: Their conversation is interrupted when Simon is kidnapped by vampires, leading to a confrontation in a nearby hotel. Their group is nearly killed until the werewolves (that share a truce with the Shadowhunters) intervene and rescue them.