Hi guys !
During Chapter 2 you'll find a coin in the shower.Take it. (49:10 in my video)
Now,at start of Chapter 3 you'll need to throw this coin in the large pit in the cave.
You can see me doing this at 1:05:25 in my full walkthrough:
WARNING !After unlocking this achievement you must quit the game and restart it,because you'll need this same coin for another missable achievement in Chapter 4 !
Happy hunting !