Call of Cthulhu

This achievement is missable.

If you use the crowbar to open the secret passage it will void the achievement and you will need to make a new game for this one.

This will be in Chapter 3 of the game in Charles Hawkins' office, in the Hawkins Manor. You're chasing a suspect who flees into the office and disappears.
He went behind the bookcase .

Check the Seaway Map on the desk and the Sailor's Logbook on the couch. You're looking for the exact point where they caught their legendary catch, on Wednesday 23rd June 1847 and that will be at 33N, 53W at the Star location.

Below is a picture of where to put the marker. The secret passage will open and will pop also the achievement at the same time.


Good luck and enjoy the game!

First get the map off of the desk. The dashes between locations indicate voyages. I can attest that the lower the difficulty, the less locations. On the lowest difficulty there's only the first Latitude and Longitude location. What's shown here is for the highest difficulty.

First put the marker to 42N, 70W
Move the marker to 47N, 55W, which is up and to the right.
Now move the marker to 49N, 61W, it's a little bit up and to the left.
Set it to 57N, 51W and the. go up and to the right
And then move it to 33N, 53W - down.

Door should open and achievement should unlock immediately.

This is at the end of chapter 3 where you have two options to go behind the bookcase where the thief you chased went behind.

Either use the crowbar you found earlier downstairs (this voids the achievement so I wouldn't bother) OR looking at the globe to the right of the bookcase, putting the marker over the correct location and having it unlock that way (which is the right way to do this)

Go to 36:00 in my playthrough 1 video to see what you need to do and where and how to unlock this. (36:50 is where to see the globes location)

Once its placed correctly, it automatically unlocks.
Hope this helps!

Playthrough 1

Playthrough 2

Hey everyone, just a quick video showing where you need to interact with the globe to get it to unlock the secret passage. The clues are on the seaway map and log, and it's the Scylla's path that activates it. You'll need to move it to 33N 53W, or the star to the East of North America. Hope the video helps!