The Blue Knees? trophy achievement requires you to find the hidden message on the mirror. It is quite a simple task and can be easily done if you are the adventurous type.
Once you have the mirror all you will need to do is examine it and the trophy achievement should then pop.
This specific trophy achievement can be unlocked whilst at Grandpa’s house.
In order to find the hidden message on the mirror, we will of course, need to find the mirror first. In order to be able to find the mirror we will need to acquire the tape and insert it into the tape machine.
We can find the tape after unlocking the storage room and finding the safe. Inside this safe is Luca’s Notebook. Whereas the tape that we need is located on the desk.
Now that we have the required tape we can safely exit the storage room and enter the newly unlocked door next to the TV. This will be the kitchen and dining room.
Once inside the kitchen we will be able to locate the tape machine, insert the tape and the power will go out. In order to get the power back on again we will need to take a trip to the basement.
Once you have made it into the basement we should then be able to locate the generator and fuse box. This will then present us with a little puzzle. The correct order is as follows; Up, Down, Down, Down, Down, Up (Note: The puzzle solution to the fuse box might be random. Another alternative is Up, Down, Down, Down, Down, Down or Down, Down, Down, Up, Up, Up). This should then allow us to boot up the generator and get the power back on.
With the power now back on our destination is to head to the bathroom, which is the door to the left of the kitchen and dining room.
When we enter the bathroom the main protagonist (Madison Hale) will mention that it smells in here and that the pipes must be clogged. Anyway go ahead and inspect the mirror on the wall.
Whilst inspecting the mirror we will find the hidden message, which reads ‘Blue Knees Is Real‘