Code of Law - Season 5 Episode 10 Helen

Derek uses Winnie as an accomplice to resolve a long-simmering issue from his past - his twisted relationship with his older sister, Helen. Razali and Isaac are temporarily distracted by a case that is turning more eerie by the hour - a group of teenagers summoning a dark otherworldly figure to do their bidding and take revenge, leading to the death of one of their own.