Da Tang Shuang Long Zhuan summary: This story sets place during the end of the Sui Dynasty, a time where multiple powers struggle for supremacy and power.Into the fray enters two orphans Kou Zhong and Xu Ziling; these two youths by many chances and luck obtain ‘The Secret to Long Life’ allowing the two to obtain profound martial abilities and a chance to rise to the top in this age of turmoil.