Naeka is a seventeen year old girl who will inherit a large fortune when she turns eighteen, however, many people might try to assassinate her and take the fortune, so her rich grandfather sends two maids, Kogarashi and Fubuki to act as her and her brother's bodyguards.

When Naeka discovers that the reason she's failing math is because her enormous breasts are taking away nutrients from her brain, she, her brother, Fubuki and Kogarashi try to find different ways of making her chest flatter.

When a group of underwear thieves steal Naeka's panties, it's up to Kogarashi to recover them. Meanwhile, a new girl, Elizabeth K. Strawberryfield, joins Naeka's class and tries to beat Naeka at everything she does.

Naeka and Elizabeth keep competing in everything. Kogarashi and Fubuki detect several bugs and spy cameras placed around the house and have to find out who placed them and try to stop them from placing more.

After Kogarashi, lacking much moral skill, bothers Fubuki about her small but constant weight gain, Fubuki snaps and goes into an extreme diet, dragging Naeka into it along the way. But soon enough, Fubuki's diet methods get out of hand.

Naeka prepares for the upcoming kendo tournament and is helped in training by her brother, Fubuki, and Kogarashi. However, the odds are against her when she is fixed against a huge adversary and when Elizabeth tries to sabotage her fights.

Elizabeth's brother, Hendrick, who has the ability to hypnotize women when they look into his eyes, wants to marry Naeka because of her fortune and huge breasts. However, Elizabeth, not wanting her brother to marry her nemesis, disguises herself as the Strawberry Mask (even though people know who she is) to try to stop Hendrick from making Naeka fall in love with him because she actually wants him for herself.

Naeka's friends, Eiko and Miwa, ask Kogarashi to bake cake for the cake shop they work in, since their depressed cook can't cook anymore. Eiko and Miwa also ask Naeka and Fubuki, who have D-cup breasts, to infiltrate their cake shop's rival shop, which has terrible cakes, but all waitresses have huge D-cup breasts. Fubuki, not wanting to wear the shop's revealing uniform, flees and tries to hide from Naeka.

Seeking to pass a math test, Naeka and the maids travel to a temple where a God grants wishes to those who please him. There she finds only women are allowed inside and this God is also a pervert who likes breasts and panties, and a psychic (revealing Fubuki takes off her clothes when drunk, and Elizabeth wets her bed when she has nightmares about crows). His prophet makes Naeka and Fubuki compete against Elizabeth and the bear-like Kendo opponent whom Fujiwara humiliated earlier, in a tennis competition where the winner would get her wish, however the rules are made up by the God as they go along.

When the president of the Naeka's Boob fan club loses his memory due to massive head trauma (caused accidentally by Naeka), only being around her breasts makes him remember things. Kogarashi and Naeka's friends embark on a plot to send the two on a date so he will regain his memory by being around her more. Naeka is obviously unhappy with this and must restrain herself from violently hurting him on their date. However over time, she can't help but feel something for him.

Kogarashi and Fubuki battle a female Masked Maid with shark teeth and powers rivaling Kogarashi, hired to assassinate Naeka. This maid, hired by a wealthy man attending Naeka's Grandfather's 70th birthday party, appears to be of the same clan as Kogarashi and reveals him to be hundreds of years old.