The Park siblings thought they had it all.  A good family, a good life, what more could anyone ask for?  However when their mother left them, their father took all his frustration and anger out on them.  Abuse and violence became part of their everyday life, until they realised their sister was not only hurt in that way as well.  Left with no other choice, they relocated to their friends' house, where hopefully, they would be able to protect their sister until things took a turn for the better.

The Park Family: Leeteuk, Siwon, Seohyun

Thirteen: Leeteuk, Heechul, Hankyung, Yesung, Kangin, Shindong, Sungmin, Eunhyuk, Donghae, Siwon, Kibum, Ryeowook, Kyuhyun

Background Information: 

Other than Leeteuk and Siwon, the rest of Thirteen lived in a mansion by themselves upon reaching university as they did not want to be associated with their parents' wealth and popularity, but instead, wanted to make it on their own. 

Heechul had family problems, while Hankyung and Yesung were supposed to be the heirs to two of the largest companies. 

Kangin and Shindong were supposed to be the heads of the largest casinos chain, while Sungmin was to become his father's heir in the stocks industry. 

Eunhyuk and Donghae were siblings who wanted to pursue their dreams of becoming dancers without replying on their parents money.

Kibum and Ryeowook were cousins who did not want to be tied down by their parents' wealth.

Kyuhyun had a family who was between good and evil; dancing with the govermnent and the underworld as well.