Story : "He speaks with no sound, and his word is law." A simple riddle. A complex madman. And the end of life as we know it. Who is Apex? What does he want? And how can Dave, VAL, and the rest of the Portal crew possibly stop him? The mystery begins to unfold in the first chapter of a 4-part epic that will change the Portal universe forever. It's got more shocks and surprises than any viewer can possibly handle. It's Portal, "Down the Tubes!" You must not miss it!