Arai went to the same middle school as Haruhi. He is bright but shy, rather normal, and is on the soccer team.

Fujioka Haruhi wins a scholarship to attend Ouran Academy, a school reserved for only the most rich and prestigious. Despite what other students may think of her, she cares little for physical appearances or the fact that she is a commoner. 
Unfortunately for Haruhi, her high school days take a sudden turn when she stumbles upon the Host Club, an elite club filled with super rich and beautiful boys who use their specific traits and charms to entertain young ladies. Even worse, Haruhi accidentally breaks an 8-million yen vase in the club. Since she is unable to repay her debt with money, Haruhi finds herself with no choice but to work for the Host Club, becoming a male host herself.

One day, Haruhi, a scholarship student at exclusive Ouran High School, breaks an $80,000 vase that belongs to the "Host Club," a mysterious campus group consisting of six super-rich (and gorgeous) guys. To pay back the damages, she is forced to work for the club, and it's there that she discovers just how wealthy the boys are and how different they are from everybody else.
 
(Source: VIZ Media) Note: Includes 14 extra chapters.