Since long ago, a bitter rivalry and feud has long existed between two
clans, the Toujo and Toyoda families. Because of this feud, it has long
been Kanade's job as a shinobi to ensure the safety of Keigo, a member
of the Toujo family, ever since childhood. Her devotion to her duty as a
guard is a source of contention for Keigo, who would rather have her as
a childhood friend than as a protector.
Of course, this
protection extends all the way to school, so when Kanade comes across
the Eishi Toyoda in class, the heir to the Toyoda family, she is
initially hostile. After an attack, Kanade soon discovers Eishi is not
exactly who she expected, and that threats to Keigo's safety do not just
exist from the Toyoda family but within the Toujo family itself.