Harry's challenge this time is the new sports culture of the "Slack Line" that originated from tightrope walking. They compete in aesthetics and creativity on a resilient belt-like line 5cm wide and 15m long. Harry learns the basics, which can be enjoyed by people of all ages, at one of the largest facilities in Tokyo. He'll try to complete various missions while keeping his balance, but will be able to pick up the slack? A world champion will show him the ropes!