Picking up from last night's episode on G4, top finishers from the NBC regional finals tackle the ultimate challenge - a four stage course modeled after the famed 'Mount Midoriyama' course in Japan. Tonight's competitors take on Stage 1, a punishing 8 obstacle course that includes a Jumping Spider, Half Pipe Attack and Spinning Bridge. Only the competitors skilled enough to conquer all 8 obstacles will move onto Stage 2. Comedian Matt Iseman and Olympic Gold Medalist Jonny Moseley host and Angela Sun ("Yahoo! Sports Minute") reports from the sidelines as the competitors continue in their quest for the $500,000 cash prize and the chance to win the first "American Ninja Warrior" title.