Haruma Kawagoe has had the lifelong wish of being an older brother. However, after a miscarriage and an operation
, his mother could not give him a little sister. Nevertheless, he never gave up on his wish.
One Christmas night, during his college days, Haruma has a huge present delivered through his window by a woman on an airborne motorcycle claiming to be Santa Claus
. The present contains the little sister he always wanted, and Santa justifies the time it took to fulfil his wish by saying that making a little sister takes a lot more time than just making an android
manga and anime follows Haruma's life as he attempts to adjust to suddenly having a little sister out of the blue, especially a little sister who has an instruction manual with material inappropriate for her age, and follows it religiously.
Tropes this show has examples of:
- Accidental Pervert: Inverted in episode 4. Makoto pushes Chitose into Haruma's apartment. Poor Haruma, he was only wearing a towel.
- All Love Is Unrequited: Taken to almost absurd levels - literally every single character except Choco is in love with someone totally oblivious.
- Captain Ersatz: "Tirantano", "Cancent Villo", "Buffalo 99", to name a few.
- Childhood Marriage Promise: In the manga, Haruma made one to his cousin Konatsu.
- Christmas Episode
- Cloud Cuckoolander: Chitose has a rather vivid imagination
- Cosplay: Not so much in the series proper, but the below-mentioned dancing theme is obviously aimed at cosplayers—and not without success.
- Crouching Moron, Hidden Badass: Yasuoka, the lethargic unemployed neighbor at the protagonists' apartment building, is actually a former detective and aikido expert.
- Dancing Theme: Neko Nyan Dance, anyone?
- Defrosting Ice Queen: Yurika.
- Erotic Eating: Done by Choco with a chocolate-frosted banana
- Eyes Always Shut:
- Tamami, With one, blink and you'll miss it exception in episode 6 As pictured in this screencap◊, her one eye partially opens for a brief moment.
- Yasuoka as well, though less as noticable
- Extreme Doormat: Chitose.
- Fanservice: Quite a bit of it
- Fluffy Tamer: Choco, with Kuro the panther.
- Furo Scene
- Girl in a Box: specifically, a little sister delivered in a present. Oh, and it's a bag, not a box
- Done twice in the valentine's day episode with a box, the first time was all just a dream, the second, well, didn't end so well for poor Choco Haruma tapes the box shut and shoves it into a closet, much to Choco's dismay.
- The Glomp: Choco loves doing this to Yurika.
- Hadaka Apron: worn by Choco at one point because her manual says that older brothers love this sort of thing.
- Hard-Drinking Party Girl: Makoto, one of the tenants where Haruma is staying, who also loves to tease their landlord.
- Hot Springs Episode
- I See Dead People:Choco meets Yasuoka's deceased daughter and wife at the amusement park.
- In the manga's finale, Choco has a similar encounter with Kuro the panther and a woman revealed to be Yurika's mother.
- Landlady: Chitose
- Lovable Sex Maniac: Makoto, although she tends to go a bit far in her teasings at times.
- Meganekko: Chitose
- No Social Skills: Choco has no experiences in life at all, and relies entirely on her inappropriate manual.
- Ojou: Yurika. Her home is huge.
- Ordinary College Student
- Panty Shot: To the point of ruining a very emotional scene.
- Promotion to Parent: Choco's arrival forces Haruma into this. Luckily he gets a lot of help (?) from his neighbors.
- Put on a Bus: Ayano.
- RetGone:Choco, at the end of episode 22 and through most of episode 23, after Haruma insists to his cousin that he has no little sister.
- Santa Claus: Well, a Santa, if not the actual old cheerful man.
- Sdrawkcab Name: Ashirai Makoto and Otokami Alisa.
- Shouldn't We Be in School Right Now?: One should worry for Choco's future, seeing as she never gets any education.
- Shout-Out: One of the last chapters features a picture of Yotsuba&!'s main character Yotsuba on a milk carton.
- Theme Tune Cameo: The ending theme, Neko Nyan Dance, is the Dancing Theme of an in-universe children's TV show. One episode centers around the apartment residents making a video of themselves performing the dance.
- Tsundere: Yurika, voiced by none other than Rie Kugimiya.
- Tsurime Eyes: Hideko, Yurika's maid, sports them.
- Not to mention Yurika and Makoto. Ayano's fiance also sports them
- Undead Tax Exemption: Choco's appearance somehow doesn't cause any problems.
- Why Do You Keep Changing Jobs?: Tamami.
- Zettai Ryouiki: Yurika.