The Filth

Tier 1

Objective: Examine Marianna Chen’s laptop

You will find the laptop to interact with on a table near Marianne Chen. On the “ACCESSING DATA” screen, type 3, then Enter.

Tier 2

Objective: Search the bog for CDC team members

You need to get close to either of the undead CDC members to get to tier 3. The closest would be Mavis Anderson, standing at (875,595).

Tier 3

Objective: Kill Mavis Anderson & Killian Forsythe

Kill Mavis and go to your next target, Killian Forsythe. To reach him, go through the pathway at (925,538), and find him wandering around (964,558).

Tier 4

Objective: Locate Ernesto Ramirez

Continue deeper until you find Ernesto’s corpse at (1006,573). Interact with it.

Objective: Read Ernesto’s tablet for clues

Now, interact with the tablet beside him.

Tier 5

Objective: Collect barrel lids (3)

Go all the way through the bog to (927,436) and interact with 3 Metal Drums here.

Tier 6

Objective: Seal the southern pipe

Get on the pipe at (803,463), kill the shade there to be on the safe side, and interact with it. It will spawn a Violent Infected.

Objective: Seal the eastern pipe

Same thing as before, but at (844,564).  it will spawn a Shade Shadowcutter.

Objective: Seal the northern pipe

You know the drill! This time, go to (830,632).

Tier 7

Objective: Kill Frank McGrath

Sealing the last pipe made Frank McGrath appear. Kill him to finish the mission.