Los Angeles, California has one of the largest and most sophisticated sewer systems in the world. Every day the amount of raw sewage that flows into the treatment facility could fill 780 Olympic-sized pools. But its old pipes are deteriorating and the system is in constant danger of breaking down. This documentary follows the path of human waste through the pipes and tunnels of the L.A. sewer system to its final destination at the treatment plant. Spend the day with members of L.A.â??s Public Works Department as their job takes them deep into the sewer system, where the slightest breakdown could have catastrophic biohazard consequences.