The Stealthy Mathematics of 'Hearthstone'

The situation in front of me looks dire. Four minions sit on the board, none of which are my own. They have a range of attack points, an onslaught that will surely deplete my remaining health points. A rope flies across the middle of the screen, igniting on the left and burning toward the right, signaling the impending end of my turn. I need to move fast.