The Sewers is a location in Death Road to Canada, the group enters a sprawling sewer system with hoards of zombies. Exploring it will allow you to find a ladder if in a siege. Interacting with it will allow you to leave and continue on your journey.
There is always one (?) special room, with a random award which can include any type of supply, or a good weapon.
The Sewer Rescue mission does not require you to find the rescuee (they will be in the first room), however you will have to escort them through the whole sewer system to get your reward.
There are two variants of the sewer siege.
River of Death
The group arrives in a huge city, conquered by undead, and sees that their only chance is braving the sewer system.
When opening the manhole, a cacaphony of groans spill out. This is not a good sign.
River of Sludge
This city is covered with hordes of undead and wreckage that has been touched by a previous fire. The group gets surrounded, and their only chance is SPRINTING THROUGH the sewers.
The group spots a desperate survivor flee from a horde by jumping into the sewer. Helping would involve having to find a safer way out.