This is Chapter 05 on the Ouran High School Host Club Manga series.
The twins are insistent upon visiting Haruhi's home, but she stricty denies. Later on, Haruhi is able to determine the difference between HIkaru and Kaoru, and the twins get into a fight after hearing about each other from Haruhi's perspective. Chaotic things ensue between the twins to make their difference evident, like dying their hair loud colors and fighting over food. In the end, they pretend to consider cursing each other, but in dismay, Haruhi threatens them, saying that if they don't make amends, they can never go to her house. The twins agree and reveal that their argument was all a plot to wrangle an invatation to Haruhi's place. However, Haruhi gets the last laugh, when she is able to tell the twins apart yet again, stunning them into disbelief.
Chapter SummaryTamaki is angry at the twins for posting a "half-naked" picture of Haruhi because he thinks the twins forced Haruhi into it, but later learns that it's been Photoshopped with the body of Tamaki and the face of Haruhi. Haruhi hears them and grows annoyed, approaching the twins to scold them. They ask if they can visit her home and when she refuses, they ask if they can spread rumors that she's a girl. A frustrated Haruhi asks how they think of her and they reply that she's their favorite toy.
A new character, Umehito Nekozawa, enters and Tamaki is terrified because he once stepped on Nekozawa's Beelzenef cat puppet and was "cursed," continuing to expand upon the events of a few days thereafter. Kyoya explains what really happened and says he's not cursed. Hikaru and Kaoru say they're bored and, after Nekozawa leaves, Tamaki lectures them for an hour and gives them punishments.
The attending guests come up to Haruhi and ask her if there are any differences between Hikaru and Kaoru, except for their hair parting, to which Haruhi replies that Hikaru's speech and behavior reveals 10% more evil than Kaoru. The twins overhear and Kaoru laughs, offending Hikaru. They get into an argument about Haruhi and Renge claims that there's now a "love quadruple" (Tamaki, Hikaru, Kaoru and Haruhi) around Haruhi. Tamaki asks Renge if she doesn't like Haruhi, too, but the girl responds that she doesn't mind Haruhi having a homosexual relationship on the side. The twins argument escalates and they end up in a serious dispute.
The next day, Hikaru shows up at school with his hair dyed Flamingo Pink, while Kaoru dyes his hair bright blue. Everyone is shocked and in their classroom, their fighting grows to include throwing objects at one another and causing one another to fall off their chairs. At lunch in the dining room, while ordering meals, they order the same items which angers them both. Honey tries to fix things by offering cake but they just get annoyed with him, as well. Tamaki nears Haruhi and asks why she's there and she replies she has to follow the twins. She mentions her lunchbox and he begins to fantasize about making him lunchbox every day. Hikaru asks if he can eat with Haruhi and she assents, trading lunches with him when Hikaru says he ordered something he doesn't like just to be different from Kaoru. Haruhi finds the Ouran lunch delicious while Tamaki then tries to swap lunches with Hikaru to get Haruni's lunchbox; Hikaru refuses.Kaoru sits at their table and tries to feed Haruhi her lunch, but Hikaru intervenes. Kaoru throws food at his brother, but Hikaru uses Tamaki as a shield and its Tamaki who is slammed. As their fight grows more intense, they throw both food and items at one other which results a big mess. When some food gets on the vice principal's face, he asks who started things and the twins point to Tamaki, after which the blond is severely lectured.
Back at the Host Club, without the twins present, Tamaki complains to Kyoya who replies he'll think of their punishment later while telling Haruhi not to worry about it even thought she really was the one who started it, ticking her off greatly. Honey mentions that this is the first time he's ever seen the twins truly fight and Tamaki agrees, adding that although he only knows the twins since junior high, they've always stuck together and a fight might not be such a bad thing as it will expand their horizons.The twins enter and continue their spat. Tamaki asks them to make up, but they ignore him. Kaoru then pulls out a Belzeeneef curse doll, saying that he's written Kaoru's name on it to curse his brother at which point Haruhi approaches and hits them both on the head saying they've gone too far. She demands that they make up and that if they don't do so, she'll never let them come to her house. The twins faces mirror a devilish smile as Kaoru turns the Belzeneef doll over where it says "Nothing" on it, while Hikaru pulls out their scripts. The rest of the Hosts are shocked at their trickery but the twins ignore them falling back into their brotherly love act with ease.
The following day, Hikaru and Kaoru are seen playing "Which one is Hikaru? Game," with their guests claiming it's easy to tell them apart with differing hair colors. Haruhi simply corrects them, saying that they've once again switched hair dyes. The twins are stunned by her ability to tell them apart because someone has crossed into their insular "world." The rest of the Hosts came up to Haruhi, excited because they "have been invited" to her house even though Haruhi denies it to the hilt.