It has been a long time...
Perhaps too long. The last time the spirit detectives were seen was over a thousand years ago. Those years, thankfully, have been very peaceful and undisturbed by any terror for the spirit world or the human world. The demon world has remained in peace with the spirit world in this time, but now tension begins to grow as the details between Yusuke Urameshi and his friends between their dilemmas grow hazy within time, and even Lord KoEnma's memory fades as the days pass.
Yusuke Urameshi...
How can words describe Yusuke Urameshi? His progress was near inconceivable after his resurrection. He surpassed many other spirit detectives and obstacles.. including the best of the best. But there would come a time when he would leave this world in death in which he could no longer come back. After outliving his wife, Keiko Yukimura, by several times her lifespan he fell into a depression as he was alone. Kazuma Kuwabara and Kurama, also known as Shuiichi Minamino, also parted through their peaceful deaths. The only enlightenment he received was out of character for him, possibly a memoir of advice from his friend Kurama, who was the smarter among his friends, or possibly Keiko. He looked greatly into the cycle of life and death. He wished to understand what had happened to the friends of his souls.
He died before he ever found what he was looking for. He was still a half human, and his lifespan was not quite as long as a full demon. Hiei continued looking after his sister, Yukina, in secret. She never did find out who her brother was, Hiei didn't have the heart to tell her that it was him even for decades. He did develop a friendship with her after Kuwabara passed away. Among the last, Hiei died a short time after. The cause of his death is unknown.
A thousand years later, Lord KoEnma sets on a new task to accomplish. He wants his spirit detective back, in dire need for the future of the spirit world. But, by no means of resurrection. He will search for the reincarnation of Yusuke and his friends at any cost.
And the search begins.