Well Watch

Synopsis
 is a side mission in the 3rd act of the base game. The heroes must intervene to prevent the Skaven from contaminating two wells in a residential district with Warpstone-based poison.

Tomes and Grimoires
 contains neither tomes nor grimoires.

Guide
Well Watch is a small map featuring a large open courtyard area surrounded by houses. The two objectives the players must defend are located opposite each other and various building and alleys with loot locations occupy the rest of the map. The mission alternates between "Stand your ground" phases during which you must merely survive and "Defend the Well" phases during which you must prevent slave rats from dumping buckets of poison into a specific well. Should one well be completely poisoned, the mission will continue with the defense phases of the poisoned well being replaced by additional "Stand your ground" phases. There is a guaranteed ogre spawn between the third and fourth well defense phases.

During the "Defend the Well" phases, the players will normally be grouped together on defense (unless one well is being deliberately sacrificed, see Tips), but during the "Stand your Ground" phases care should be taken to coordinate loot-gathering runs, hold-up locations, and revive runs. If communication is difficult, more experienced players should either keep an eye on less-experienced ones to prevent them from being isolated and killed as the players scramble in all directions, or say something like "come with me if you want to live".

Sample Strategy
One popular strategy is to quickly proceed to the left after the initial drop down and then proceeding all the way up the stairs in the apartment building next to the Tenement Well to the roof, grabbing loot all along the way. Allow the Skaven to poison the first well completely, and then head to the second well passing along the left-edge of the map to proceed through the map is to collect more loot. By this time, the first "Defend the Well" phase for the Burgermeister's Well will be due, and the players can hold out near the well, taking advantage of the natural rat-funnel of the courtyard stairs while watching out for rat and special spawns to their flanks and rear. Kill the ogre when it shows up, defend one more wave of bucket-rats, and you're on your way home.

Well Watch in particular has developed a vast number of strategies. If the one above isn't working for you (or you wish to defend both wells), check out Youtube or ask on Reddit.

See the "Advanced Map Strategy Guide" for more details and strats.

Tips

 * Of the two wells, it is easier to defend the second (Burgermeister's) well. Ignoring the plight of the commoners' well while you pillage their homes for resources is highly recommended.
 * Only slave rats carry buckets of poison, so prioritize killing them during "Defend the Well" phases. On lower difficulties it takes a minute or more for the rats to poison a well, but on cata the well will be lost in moments if several slave rats make it through your defenses.
 * There are two guaranteed ammo crates on the map: one on top of the tenement building near the first well, and one in an attic area to the right of the second well (looking towards the courtyard). This "attic crate" can be accessed through the floor, allowing the players holding out at the second well to skip a lengthy jumping detour in order to top up their ammo. If you're having trouble locating the crate from below try "ping-scanning" it first.
 * Bombs (and fire bombs in particular) are very valuable on this map, as they can quickly "reset" a situation where multiple rats are beginning to poison a well. Blow them up and re-establish initiative, friendly fire or not!
 * If one or more players need to revived, you can delay the start of the next "Defend the Well" phase by leaving some rats alive as you proceed to revive your teammates.
 * If a player dies, you can force them to respawn at your feet by heading to the corridor opposite the first well and adjacent to the pig sty.

Gameplay Videos
Cataclysm team run from Tirrikface ft. "holdout at second well" strategy:

Deathwish run with Jsat & crew ft. "apartment holdout" strategy: