The Extreme summary: Han Siwoo lost one leg when he was young. He was bullied in school and stigmatised by people who met him. Using a "smart leg", he started skateboarding and after displaying excellent balance and skills he managed to join the "extreme crew". He has to overcome his rivals and obstacles in his way. Will Han Siwoo be able to overcome all these things and prove that he is capable to participate in the national team selection?