The members of the Host Club plan an event to help Tamaki get over his separation anxiety from the Host Club, and even Haruhi gets in on the action. Will the bonds of friendship between Tamaki and Haruhi become bonds of love? 
The Host Club are holding an orienteering competition and Haruhi convinces Tamaki to enter with Kanoya. At 4 locations the participants have to complete a challenge and then choose from a selection of ingredients for the 5th challenge - to cook a curry. Tamaki chooses terrible ingredients, but Kanoya is too submissive to tell him he's wrong. During the challenge Tamaki realises that, although Kanoya is more suited to him and even resembles Haruhi, she has a very different personality and it's really Haruhi that he loves.
Tamaki reminisces on how stupidly he has acted towards Haruhi, particularly his insistence on treating her like a daughter. He remembers how his father's actions to choose love broke up his family and he's scared that he will do the same to his Host Club family. This reminds him of how Hikaru said that their bond won't be easily broken. Mori later also tells him to be honest with himself and know that everyone in the Host Club trusts him. At the curry challenge, Kanoya has a difficult task to make a curry out of terrible ingredients, but as a cook's daughter she gets back her confidence and does well. In the final 'truth' challenge Kanoya admits that she misses her dad and Haruhi encourages her to be honest with her family about her feelings. Haruhi also tells off Tamaki for keeping secrets from the Host Club and lets him know that they all want to support him – whatever it is! Tamaki realizes that, despite being scared of losing his friends, he is ready to tell Haruhi how he feels.
In a flashback, Tamaki tells Hikaru that he also loves Haruhi. Walking to school, Haruhi is still wondering what Tamaki's secret is when he arrives on a Segway. He tries to confess but starts babbling nervously and makes Haruhi run away. Tamaki is full of self-confidence and thinks it's a sign she loves him. Hikaru tells Tamaki not to presume that he knows her feelings, but Tamaki of course doesn't listen! Meanwhile, Kanoya tells Haruhi that she was depending on Tamaki too much, and probably just liked him as a father figure. Haruhi disagrees because seeing them together made her jealous. Haruhi goes to the clubroom wondering what she sees in Tamaki – only to find him singing 'Happy Birthday' to himself like a fool. Tamaki's confidence evaporates on seeing Haruhi and he hides and starts to wonder whether he is right to assume she likes him. It is revealed that it's Haruhi's birthday next week and Tamaki and Hikaru both imagine buying her a present that will make her fall in love with them. Kyouya gets a phone call and reveals he knows something about the "lying lawyer" Kousaka.
Kyouya has found out that Kousaka has been secretly and regularly meeting with Tamaki's grandmother (Shizue Suoh), and also has a link to Haruhi's family. Kousaka visits Haruhi's dad and it's revealed that she was classmates with Haruhi's mother. She warns Ranka that Haruhi should stay away from the Suoh family and Ouran. Meanwhile, Tamaki and Hikaru are trying to work out the perfect birthday present for Haruhi – finally agreeing that she'd like something low-cost and useful since she's a commoner. They end up both giving her the same thing - a Prawn Rice Water Flowing kit - but Haruhi prefers the Shiitake Mushroom kit from Ritsu Kasanoda.
It's the last day before Mori and Hunny graduate from Ouran, and the club are shocked to find out that they won't be together at university as Mori is pursuing Law and Hunny pursuing Science and Technology. Haruhi finds Tamaki asleep in the clubroom and reflects on how badly she's treated him over the last few days and how hard he is taking the departure of Mori and Hunny. It's clear that something is on Mori's mind, and the Host Club think he's sad to be leaving Hunny's side. Hunny demands Mori tell him what's bothering him, and Mori says he will – after they duel.
 Taken directly from the back of the book