Izumi and Mitsuki have run away from home and are looking for work. Where to go? They happen to stumble upon the house of 14-year old billionaire Yoshitaka Nakabayashi, who's looking for maids. Yoshitaka lets the girls stay and relax, but leaves them maid outfits to change into when they get out. Shortly before they leave, Izumi breaks a very expensive pot, and so she and her sister are roped in working to pay off their debt. Throw in a perverted alligator, a third maid from Yoshitaka's school (also a schoolgirl lesbian), and it all takes off from there.Not to be confused with They Are My Noble Masters.
Air-Vent Passageway: Used when they are trying to rescue Mitsuki in the fourth episode, but it is so loud the Mitsuki-chan Defense Squad hears them coming immediately.
All Women Are Doms All Men Are Subs - Yoshitaka never succeeds in fulfilling his sick demented fantasies despite his power over the girls (and Mitsuki's apparent eagerness). In fact, he's tied up and whipped by Izumi and some French girl he tries to seduce at one point.
Always in Class One: Izumi and Yoshitaka are shown to be in class 2-A. Being in he same class is convenient for Yoshitaka, but isn't for Izumi for the same reason. Anna is also in that class.
Amusing Injuries: Yoshitaka is hurt quite a lot for the sake of the comedy. Often deservedly so. This is even taken Up to Eleven when we can see his face restoring real time after it became unrecognizingly deformed all this while talking back to Izumi.
Art Shift: The anime and the manga's art styles are very different. Also, Pochi in the first manga volume is drawn more like a realistic alligator, but becomes the cartoonish blimp he's most known as in the next volume. The characters actually bring this shift up in one chapter, with the explanation being that "Pochi has gotten fat."
Author Avatar: Mattsu is portrayed as an alligator, and Asu as a hamster. Due to the fourth wall never having existed for the manga in the first place, they are literally part of the main cast by now.
Big Fancy House: Complete with a front and back yard the size of several parks put together. Mitsuki was even able to let her defence force build an full scale indoor beach without the other even noticing it!
Bowdlerize: The German release ups the girls' ages by three in the dub and the sub.
Buxom Is Better: Izumi gets a lot attention from other characters because of her large breasts.
Characterization Marches On: Word of God points out that in early chapters, Anna is supposed to be the "innocent, naive character", but he decided to change her and make her a Yoshitaka-level pervert.
The Chew Toy: Izumi and Yoshitaka. Usually one is the cause of the other's misfortune.
Chivalrous Pervert: Pochi the alligator, particularly in the manga. The author's notes in Volume 2 even note that the big difference between him and Yoshitaka is that Pochi actually gives a damn about the girls he pursues; as people, not objects.
Comedic Sociopathy: This trope is the main source of the series' humor, not to mention in the most extreme ways possible.
Costume Exaggeration: A guest character agrees to have a competition with the show's resident lech. The former excels at designing several costumes with noticeably less Costume Exaggeration than the latter, before the lead girl is convinced there's not enough of a functional difference to bother changing employers. (That and the new employer loves crossdressing, which is a step too far for the girl who gets abused on a daily basis by every other main character.)
Die Hard on an X: In the mansion itself on the fourth episode, complete with hidden guns bandaged in the back of the protagonist character, and even quoting the title "Die Hard".
In the Blood: Izumi and Mitsuki's parents; the father is alot like Izumi and the mother is alot like Mitsuki.
Jerk with a Heart of Gold: Yoshitaka constantly walks the line between this a straight up Jerk Ass as he is revealed to have ulterior motives. In the final episode he seems reformed, but it is all eventually revealed to have been a plan to renew Izumi's contract. However, some internal dialogue, which he would have had no reason to fake since the other characters couldn't hear him, suggested that he may have been serious about wanting to marry Izumi. So, it's up to the viewer to decide which he is. The manga is an aversion because Yoshitaka is irremediable.
Opera Gloves: As seen above, Izumi, Mitsuki and Anna all wear long white gloves (with black cuffs at the top) as part of their Meido outfits.
Parental Incest: The girls ran away from home in the first place, because they got tired resisting their father's constant sexual advances.
Father: I love you both just as much as your mother! Izumi: Ewww! Father: Just as much!
Priceless Ming Vase: Izumi debt start with her smashing a vase worth 5,000,000 yen. Since she smashing something just about every time she is cleaning up and the house is full of expensive things you can probably guess which way the debt is going...
The Rival: Seiichirou for Yoshitaka and Takami for Izumi (though the latter is subverted in the anime, where Takami is actually just acting the part of Izumi's rival as part of Yoshitaka's plan.
Token Yuri Girl: Anna towards Izumi, to the point of Stalker with a Crush. Izumi doesn't exactly reciprocate the feelings, but the cast (including Izumi, with promises) do use Anna's obsession to their advantage on occasion.
Unwanted Harem: Izumi has a rather mixed collection: her villainious master Yoshitaka, her fellow maid and resident lesbian Anna, the perverted alligator Pochi, and crossdressing Seiichirou. And no, she don't want any of them.
Villainous Crossdresser: Yoshitaka's cousin Seiichirou. He is nice enough in the anime, but kidnapping Izumi in the last volume of the manga and trying to manipulate her certainly don't earn him a place among the good guys.