BIONICLE Adventures 1: Mystery of Metru Nui

Mystery of Metru Nui is the first Bionicle Adventures book and came out 2004.

Story
Vakama receives a vision which tells him that the six Great Kanoka Disks must be used to stop the Morbuzakh, and the names of the Matoran who know their locations. There is no time to tell Turaga Dume of their transformation, and the Vahki automatically designate these unknown beings as threats - possibly impostors of Toa. The Toa set out to find Lhikan and the Great Disks, unaware of their newly-granted mask powers. After finding the disks they expect to be accepted as true Toa.

The six Matoran who know the locations of the Great Disks - Nuhrii, Vhisola, Orkahm, Ahkmou, Tehutti, and Ehrye - go missing after Ahkmou helps the Dark Hunters lure them into traps.

Nokama learns that Vhisola knew that the Great Disks could be used to stop the Morbuzakh, confirming Vakama's vision. She rescues Vhisola from the roof of the Great Temple, where Nidhiki had chased her.

While searching for Nuhrii, Vakama is nearly killed by molten Protodermis - Morbuzakh vines were able to tip a vat of it because Nidhiki had sabotaged the vat controls and caused them to move more slowly. Vakama learns that the Morbuzakh dislikes cold. Vakama rescues Nuhrii from a nearly collapsed building.

Whenua finds Tehutti deep in the Archives sub-levels - a Rahkshi of heat vision had been set loose to chase him. Whenua releases a Muaka to fight the Rahkshi, and while both are distracted, Whenua and Tehutti escape.

Impatient, Nidhiki and Krekka threaten Ahkmou, telling him to try harder to get the Great Disks.

Nuju rescues Ehrye, and fixes a spreading crack in a Knowledge Tower (which Nidhiki and Krekka caused).

Matau rescues Orkahm from sector three, an area of Le-Metru devastated by the Morbuzakh.

Onewa "rescues" Ahkmou from the top of a statue, although Ahkmou was never in any danger. Ahkmou runs, knowing his life is in danger. Onewa catches Ahkmou at a Chute station.

Characters

 * The six Toa Metru/Turaga
 * The six Toa Nuva
 * Takanuva
 * Lhikan
 * Ahkmou
 * Nuhrii
 * Vhisola
 * Tehutti
 * Orkahm
 * Ehrye
 * Kapura
 * Nidhiki
 * Krekka