The Sewers was originally made by a GM named Craft.
The starting mission is located at 2990, 2355, above ground = false. It is activated by examining the sign.

I made several improvements, which are listed below.

The Shrines mission consists of 30 shrines. Each shrine must be completed in sequential order (the dungeon's linear path) as each will progress the mission a percentage of completion. If a player misses a shrine they must go back and do that shrine to complete the mission, and every shrine thereafter that they have missed. If a player does not interact with all shrines they will fail to complete the mission.

I've set up a gnome at the beginning so players can reset the Shrines mission.

There are three coffins missions. Each are independent from the other. The coffins were initially set to expire in 1 hour which can be confusing to a player when they get a fail message. I removed the timer and added trigger tiles on the end ramp out to reset the coffins missions if they somehow didn't reach 100% completion, which has happened.

I noticed that there was a need for cotton replenishment for players during the mission. I created a cotton replenishing mission at the mid point of the dungeon; a BSB that gives out cotton once. There is a trigger on the ramp out to reset this mission.

The shark mission is stand-alone and not required to complete the shrine mission of The Sewers. It is simply there for the player to test their fighting skill, if they so choose.

I will add more info as I glean it from the area.