Here is a 100% walkthrough of Chapter 4: Mountain Trek including all the secret locations and the missable achievement
Get a clew.
Secret / Collectible #1 - 1:13
Secret / Collectible #2 - 2:17
Secret / Collectible #3 - 4:32
Secret / Collectible #4 - 5:36 (Get a clew Achievement/Trophy)
Secret / Collectible #5 - 9:10
The Get a clew achievement in Unravel worth 58 pointsGet the secret hidden in the mountain maze