Seeking quietude for study at an elite academy, honors student Haruhi Fujioka comes upon the school's Host Club - six elite boys who host parties for girl classmates - and becomes its newest and most reluctant member.
Kanako the chronic host-hopper (a girl who changes from host to host at regular intervals) gets the attention of Host Club, who decide to target her for happiness.
Tamaki, jealous that the twins get to spend far more time with Haruhi than he, wants her sex revealed, but that may occur on its own with school physicals coming.
A delusional girl obsessed with Sims (virtual people) believes Kyoya (who looks like one of them) is her fiancé and forces herself on Host Club as its new manager.
A desperate 5th-grader comes to Host Club demanding to be taught how to be a ladies man but his negative reactions toward the hosts call into question his motives.
Enjoyment at a family-owned indoor tropical pool park turns into a Jurassic Park-like disaster for Host Club members due to discarded banana peels and live alligators from the tropical exhibit.
The Zuka Club, from a rival all-girls academy, challenges the Host Club for the fair hand of Haruhi, whom they feel has been woefully mistreated by the enforced subjugation of her superior gender.
Is Haruhi dreaming when she falls down a rabbit hole in Music Room #3 and meets Alice in Wonderland characters who, like characters in Oz to Dorothy, all look strikingly familiar?
Haruhi takes a summer job at the bed and breakfast of her father's friend, which bends the host boys out of shape over being abandoned, so they follow.
Hikaru and Tamaki's insecurities show when Haruhi runs into a male friend from middle school days, but while Tamaki recovers, Hikaru does not, so Kaoru steps in for his twin's sake.
On the last day of summer vacation, Tamaki decides the elite members of Host Club should go on a field trip to observe commoners in their natural setting - a shopping mall.
The Zuka Club girls from Lobelia Girls Academy get Haruhi to star in their annual theatrical production honoring President Benio's late mother, but it's really a plot for revenge.
Haruhi's class puts on a Halloween After Dark Test of Courage Tournament, where the Hitachiin twins take delight in tormenting their multi-phobic class rep/teammate.
The heir to a crime syndicate comes to Host Club to be Mori's apprentice, hoping for a share in his secret of having friends while owning a scary face.
The Ouran High School Fair provides the catalyst for a pair of disapproving fathers to tip back into their sons' lives, with public humiliation for one and an arranged marriage for the other.
