This is a missable achievement. Toward the beginning of Chapter 5 - The Secret, you will be given the task of searching the garden in the snow. There are five objects you need to find to unlock the achievement, but a warning! If you interact with the gate to leave the property you will automatically be brought back inside and cannot return to find any objects you have missed. The five things you have to find are:
* Faint Footprints
* Expensive lighter
* Garden tools
* Milk bottles
* Fallen bird feeder
Once you have found all five and unlocked the achievement, it is safe to click on the gate.