The Return of the Su

The moment Qin Lang saw Qin Chuan, tears finally streamed down his face uncontrollably. A cry of anguish escaped him, thousands of words stuck in his throat, unable to be uttered!,For this one glance, I have yearned for a full nine hundred years!,The doctors in this world can't cure this poison. Who is it, and what kind of grudge do they have against their father to inflict such a deadly blow。