I don't know what the requirements of the new Sherlock game will be.
I don't think Frogwares has announced them yet.
However the 720m is not a high end card.
http://www.notebookcheck.net/NVIDIA-GeForce-GT-720M.90247.0.htmlDepending on the clock rates, the 3D performance of the GeForce GT 720M is somewhat above the old GT 620M, but clearly below the GT 630M in most cases. This is due to the 64 bit memory interface, which limits the performance noticeably. In comparison to the competition, the 720M offers a performance similar to the HD Graphics 4400/4600 or Radeon HD 8570M. Overall, the card is placed in the lower performance segment. Current games (as of 2013) will run fluently only in low settings.
According to the Notebookcheck article, the 720m is an "entry level" card based on the 540m.
According to Google, Sherlock Crimes & Punishments will use the Unreal Engine 3. Whether the card works or not with Crimes & Punishments may depend on how much dedicated video memory your particular card has (the 720m can have up to 2GB) and how high the specs for Crimes & Punishments are.
So you may want to try a demo before buying the game.
We'll have a better idea of whether it will work when Frogwares releases the system requirements for the game. I'm guessing it will run the game (as long as the card has 2GB video memory, or at least as much as the game requires), but it may be sluggish and you will probably need you to turn down game options.