Valentine, and to an extent the Universal Will, desired to enter the Cube, a structure built by That Man located in the Backyard that is capable of manipulating information in the Backyard thus influencing the real world.
Unfortunately, they need a "key", the gear cells of Justice, to open it. Thus gears all over Illyria began to disappeared and sublimate by Valentine and her army in an effort to find the key. Eventually, Dizzy the Maiden of the Grove and Justice's daughter was targeted and was close to being sublimated; thankfully High King Ky Kiske manage to use Thunderseal and froze time around her thus saving her from a grim fate.
Unfortunately, with the location of the "key" revealed to them, the Vizuel army launch an all out attack against the capitol of Illyria in order to claim her.
Despite being armed with magic, they were ineffective against the Vizuel army and the city felled, with King Ky being trapped in a seal.
Sometimes later, Sol Badguy, Sin Kiske and Izuna arrived and fight their way to the castle, clashing with Valentine in the process. The group manage to reach the throne room but unable to free Ky from his seal so Sol and Izuna traveled to Ganymede to get Dr. Paradigm help while Sin was left behind to watch over Ky.
After passing Paradigm's test and repelling the Vizuel invasion of the archipelago; the doctor along with several of his Gear companions agreed to travel with the Sol back to Illyria. Paradigm was able to release Ky, but Sin was captured and brainwashed by Valentine, which mean she was able to obtain the "key" since Sin was Dizzy's son.