Ryuko has taken up residence with Mako's family, the Mankanshokus. She
names her talking sailor uniform "Senketsu." The next day, she and Mako are going to school when Mako is suddenly ganged up on by the Tennis Club.
Ryuko tries to rescue Mako, but for some reason Senketsu won't activate,
and Ryuko finds herself being no match against the Tennis Club President
Omiko Hakodate. She is saved by her homeroom teacher, Aikuro Mikisugi.
From him, she learns that Senketsu is a special kind of clothing called a
"Kamui," and that he activates by drinking his wearer's blood.