Newbie Helper:
Welcome! I have a mission for you. Do you see the Gremlins all around us? One of them has stolen a precious Blue Gem from me.
You must defeat the Gremlins and recover the Blue Gem.
To target a Gremlin for attack, simply move your cursor on top of it and click the left mouse button. The cursor will change into the shape of a knife; when that happens, click the left mouse button again to begin attacking. 
If you successfully return the Blue Gem to me, I will give you reward!