Listen carefully, for it is a matter of life and death. Incredible medical journey is about to begin. You and your submarine will be reduced to microscopic size and injected into the blood stream of a critically ill patient. Your mission is to go through a narrow network of veins and destroy life-threatening blood clots, located near the brain of the patient. Protection of cells, bacteria, enzymes, antibodies, and not just a few odd obstacles you find along the way. Get ready for one fantastic journey!