404 Not Found is a main mission in Watch Dogs: Legion.
Your task is to follow the instructions of the leader Nowt and head to Somerset House.
Here’s a walkthrough of 404 Not Found in Watch Dogs Legion.
Meet Nowt at Somerset House
Head to Somerset House. The location is provided in the map.
To enter the building, you need to open the locked door.
Inside, you should see a trap nearby. Make it explode to open the door.
Take out the guards along the way and continue to go all the way up.
Access Nowt’s AV Server
To access the server, go to the room with the ctOS hub. Interact with it.
Go to Nexus Tower
Leave the area when you’re done. The next location is Nexus Tower.
Before you enter, you should disable the alarm. Hijack the camera inside and disable the alarm.
The officer will check on the alarm and you have to sneak in before the alarm’s up again. Take them out if possible.
Erase the quantum computer
Look for the quantum computer inside the tower.
You have to be careful here as there are two turrets, one on each side of the computer.
You may want to raise the barrier to block the turrets first. Disable the computer by interacting with it.
Leave the area to proceed.
Discover Nowt’s big contract
Get to the next location marked on the map to discover Nowt’s big contract.
To enter the Broca Tech building, use the stairs at the side. There’s an object you can stand on before you climb onto the staircase.
Keep going up all the way. You will encounter guards along the way.
At the rooftop, there are more guards and drones.
Get to the ctOS hub inside a locked space. As the door is locked, summon a spiderbot to go in through the hole.
Use the spiderbot to interact with the hub.
A cutscene will load and the mission ends after you leave the area.