Nice Old Town: A series of disappearances

You are a tourist passing through Nice for the day, before moving on to visit other surrounding towns of the French Riviera. 

You are admiring the Monument Centenaire, when a strange feeling makes you turn around to look on the opposite side at the sea. And you see them: seven men are floating from the horizon towards the monument, towards you.

The closer they get, you realize you can see through them! They bear themselves as if they are men of great importance, yet a shadow of fear flickers in their eyes. Who are these ghosts? You must find out!