In the case of Temple of the self you are required to unlock a red lock box.
It requires a four-digit code.
This is the low-spoiler guide for "The temple of the self" puzzle in Chinatown Detective Agency. Unlike in normal walkthrough, you get gradual hints on how to solve the puzzle. Click the big button below to see your first hint. If the hint contains a spoiler, you will be warned about it before clicking.