A Secret Letter from my Father Walkthrough – Unlock the bookshelf
4. Use the key on the keyhole then enter the password in order to unlock the bookshelf which covered with a steel grating.
a. Tap on (1).
b. Tap on (1) to take the key then tap on (2) to turn on the power.
c. Tap on (1), (2) ,(3) and (4) to open the steel grating.
* You have to go and check the hint once!
d. Steel grating opened.