Story
This is the continent of Marvel.
A strange world where fashion coordination has become the standard for all things, and social status, reputation and war outcomes are determined by Coordination Battles.

It's year 672 of the solar calendar.
The great fashion designer, King Saya's posthumous works are being fought over in an outburst in the border city, Reualto.
This Coordination Battle continued over nine days, and was later called the 'Nine Days War'.
Among the posthumous works 2 were obtained by Karfa Kingdom's 'Goddess of Regeneration', and the rose treasure chest became a light-pink haired girl's.

It's year 680 of the solar calendar.
A girl from another world came down to this land.
A girl with the same colored hair as the mysterious girl who got the rose treasure chest.
ーーHer name, is Nikki.