Unfortunately, I am not too familiar with this part of the series,
but fortunately, I still remember the basic framework of it all.
There are the Shiseijuu which Reikai looks after (as in, rules,
supervises, whatever), and they have broken lose, causing Koenma to
panic, as the leader of the four has taken a flute which can hypnotise
people with its spell. Susaku plans on ruling the whole of Ningenkai
with this flute. Yuusuke assignment is to stop him, with Kuwabara,
who wants to show off his power, and Kurama and Hiei were also sent
as a punishment for the theft of the Reikai treasures.
There are certain lackeys of Susaku that the group has to pass
before reaching the top of a castle where Susaku himself is situated.
All Yuuuske's friends do the work for him, as they wanted him to save
his reiki to fight Susaku. Kuwabara is first, and is faced with a
giant tiger creature named Byakko. After a fight, Kuwabara finds
himself chased by tigers. But no problem, the great fighter soon
sticks all tigers on his stretched Reiken, and ties the sword around
a tower. Infuriated, Byakko challenges Kuwabara to a fight on
platforms where lava boils underneath. Kuwabara finally manages to
push Byakko off the last tower, and his bandages catch on to a piece
of rock sticking out, saving him from the lava.
Kurama is up next, and his opponent has the ability to piece himself
together, no matter how badly sliced. His fighting ground allows him
to travel underneath and attack his opponent from below. After seeing
that he could not kill Genbu with his bare hands, Kurama produces his
weapon, rose whip. However, slicing the creature was still a futile
attempt until Kurama spotted the origin of power that enabled the
pieces to fly back together, and promptly destroyed it. Genbu
shatters and dies.
Hiei's match was really nothing. His opponent was an ice weilder
named Seiryuu was relatively slow compared to Hiei, and thus, was
readily turned into sword fodder.
On reaching the top of the castle, the group of four are faced with
mindless zombies. Working together, the get on each other's backs,
to form a ladder which Yuusuke can jump on to reach a window, the
entrance to the tower where Susako is. Susako was seated on a chair,
in front of a monitor with an annoying bird on his shoulder. It was
an even match between him and Yuusuke, but tide turns when Susaku
turns into seven people, summoning lightning as his weapon. However,
like all dumb villains, Susaku stupidly showed Yuusuke how his
girlfriend was about to die in horror and panic at school. This only
hardened Yuusuke's will to get up and fight again and again. It turned
into a rough tough and whole sale use of youki and reiki and
willpower, causing the roof of the tower to shatter, and earthquakes
to run through the whole building.
Susaku was finally defeated (after many recycled anime), when he
used his own life force to defeat Susaku. The flute was destroyed
and Keiko and Botan were safe. Kuwabara gives up his last bit of
strength to save Yuusuke. Kurama and Hiei send them back off to