With two artifacts under his belt, Yusuke heads for his most dangerous challenge yet – the ruthless demon Hiei. But unbeknownst to Yusuke, Hiei is chasing him, and kidnaps his girlfriend Kayko! Unless Yusuke can retrieve the antidote inside Hiei's Shadow Sword, Keiko will become a brainless, monster slave! Can Yusuke close the case?

Kuwabara's body lays broken. Shorin is nowhere to be found. And with Yusuke's energy dwindling every minute, the evil Rando reveals his true and monstrous form. Now, can the injured Yusuke battle the human-hunting demon and close the case? How can he, when Rando has ninety-nine deadly techniques in his arsenal.

One of Yusuke's teammates has been badly injured, and Kuwabara insists on fighting the next enemy all by himself -— revealing his amazingly improved Spirit Sword! Before the bickering group can disagree, a ferocious roar slices through the castle. Byakko, the second Saint Beast, is waiting!

Yusuke's Spirit Detective team continues toward Tarukane's mountain stronghold, facing a small army of grotesque demon guards. It seems an alliance has formed between human criminals and demon mercenaries, with money as the bottom line. Yet Kuwabara plows fearlessly ahead declaring he's in love with Yukina!

As Team Urameshi boards the ship, the preliminary round begins. The Masked Fighter is the one to fight, as she knocks out the demons with a Shotgun, causing a riot against Team Urameshi on the ship. The team then begins to fight, knocking out many demons, even killing a few, when they reach Hanging Neck Island. When they reach their hotel room, they are greeted by two mysterious characters, from Team Rikkuyukai, the team they are to face in the first round of the tournament.

Round two of the tournament arrives and Team Urameshi must face Dr. Ichigaki’s fighters, a group with a habit of chopping off their opponent’s heads! Will Yusuke be the doctor’s next guinea pig?