In a Nutshell: This is a first-person, mystery adventure with some puzzle solving that may, or may not, have anything to do with the overall story.
(from the game’s website)
“Somewhere beyond the bright piazzas and open markets of the Venice Carnevale lurks a masked thief. Despite months of investigations, the Italian police remain helpless as stolen treasures vanish in the night. That’s why the authorities asked you, as detective Nancy Drew, to join the case, to infiltrate a dangerous crime syndicate and catch this phantom thief before he or she destroys the heart of Venice!”