It's so interesting to get a look at what Charlie Chan looked like in the Chinese films from that poster.
Notice that Charlie's Number 1 daughter is wearing some sort of weird glasses.
I was pleased to see that this links up with part of the plot synopsis that I attempted to translate...
"Afterwards, Charlie Chan invents spectacles that may possibly reveal the stealth technique used. However, he must wait to use the spectacles when they cannot be found, so the case becomes deadlocked."
Amazing to see the 'spectacles' mentioned in the synopsis.
