More so than the Police Station the Sewers can be dangerous if just for how confusing the area can be. Run past the locked Treatment Facility door and around to the left. A panel slides, revealing Bishop Plug. Once you head through the first gateway, look to your left to find the Queen Plug as shown in the image below. Or, better yet, head up the stairs first and save. We hoped so hard that killing him would prevent the G-Adult from appearing later. Walk through the door into the next room, collecting the Red Herb on the shelf to your right.
On a wall to your left just outside of the Workroom Door, interact with a plug to receive the Electronic Part. Lower Waterway Head to the west end of the Lower Waterway, then slide down the slope there. If you're curious about then take a look at the models and real life people scanned in to give life to Leon, Claire and Marvin. Pick up the Gunpowder, Handgun Ammo, and the Jazz Festival Flyer. G will return as G Stage 2.
Interact with it to shove it out of the way. Turn to your left, and shoot the on the ground. Turn to your left, and head through this gap in the fence. Climb the ladder up to the Control Room. Now test out your new ammo with a headshot to the zombie playing dead nearby. Pick up the Hand Grenade sitting along the left wall. Panel opens and Knight Plug is found.
Capcom via Polygon Take the right at the intersection and keep following the tunnel until you come to a fork. Main Power Room Once the door opens, head down the stairs and grab the Blue Herb and the Green Herb. The Knight and the Pawn are in the panels with their pictures. Descend into the sewage and head right. But before you do that, backtrack up the ladder and head to the Workroom. Climb out onto the landing on your right, then head up the stairs.
Take the lift elevator up to the second floor. Capcom via Polygon Go to the office within the office, and open the drawer in the desk. Now we finally have all 3 plugs that we need! Bottom Waterway Capcom via Polygon Climb down the ladder, and collect the Green Herb next to the corpse. G will return as G Stage 2. The plug puzzle is found at and requires six plugs: Pawn Plug provided , Knight Plug provided , Bishop Plug provided , Queen Plug Supplies Storage Room , King Plug Supplies Storage Room and the Rook Plug Hallway near Workroom.
Look at the side of the safe to find its combination: Left 2, Right 12, Left 8. In this playthrough, the Upper Waterway has three zombies in it. Floor will give way dropping Leon to level below. Well, at least this one's got some directions. The letters S, Z and F are circled. As soon as you can sprint past him through the door he came in through, do it. Press forward a little bit, and you can hop up on a ledge to your right.
Underground Stairs This is the area where you first entered — the bottom of the staircase. The ones that are missing are the Queen, King, Rook. Combine a Green and Blue Herb and eat it to cure yourself. It tells you that the combination to a safe is written on the side of it in chalk. Then use the handle on a floodgate to get to the Bottom Waterway, where many poison monsters lurk. Better to just ignore them and that door, which leads to the Sewers Key that we got another way. Interact with the filing cabinet covered in yellow tape to move it and reveal an entrance to an elevator or lift, if you prefer.
Open the drawer in the desk there. Do that twice, and you win. This is really embarrassing, and i may have just overlooked it, but i cannot find all the plugs rook, knight, bishop, king to that door. You can combine the three herbs you just picked up in the last 45 seconds to create a Mixed Herb G+R+B. Sprint over to the panel and hit the button. Now head through the path you opened, and hug the right wall. You can now safely discard the T-Bar Handle.
Inspect diagram on wall then hit Red Switch. You just have the get there first. However, finding all three of the missing pieces requires solving a puzzle of its own. Run around the room doing your best to avoid his gigantic hand. After that, you can poke around a little. Now drop down, and go to the socket that still holds the Queen plug. Walk through the door into the next room, collecting the Red Herb on the shelf to your right.