As you explore Darkwater in Call of Cthulhu, you'll find two opponents who will block access to warehouse 36, your mission's goal. Since you can't use strength to get rid of them, you need to use a trick to lure them away.
To do this, you will need to encourage two drunken sailors to help you. You will need a liquor to do this. To get it, go along the coastline of Darkwater - avoid the dead whale and go to the small houses that can be seen in the distance.
Pick the lock on the door of the first house on the right to get Bottle of liquor.
Now go back to the drunkards and start a conversation. At the end of the conversation you will be able to give them the alcohol, in return they will draw the attention of the guards, thus opening a way for you to slip through. For your efforts you will receive an additional achievement - No prohibition in Darkwater. The whole process was described in detail in chapter 2 of our walkthrough.