Kyoya Hibari - One Day Observation Report is the first Katekyo Hitman Reborn! Drama CD to be released. It focuses on how Tsuna, Gokudera, and Yamamoto try to find out Hibari's activities for one day.
Synopsis
Just as Tsuna finishes bathing and prepares to go to sleep, Reborn suddenly gives him a task that involves turning in a report of Hibari's daily activities. The next day, Tsuna is at a loss on how to complete the report. If he carelessly approaches Hibari, he will be bitten to death but if he fails the task, Reborn will kill him. While on his way to school, he meets Gokudera and then Yamamoto who ask him did something happen. Tsuna explains his problem to Gokudera and Yamamoto, who decide to help him out. Gokudera suggests beating and then catching Hibari so they could make their report, an idea that was immediately turned down by Tsuna. Yamamoto then proposes to find Hibari at school first.
Once at school, the three of them check in the Reception room but doesn't find who they were looking for. Next, they start searching around the school since they think that Hibari might be patrolling. Still, they are unable to find Hibari. Yamamoto voices out loud that Hibari might be absent but Gokudera interjects this since Hibari loves the school too much for that to happen. This reminded Tsuna of that one time when Hibari got hospitalized because of a cold, which somehow resulting in him getting beat up by Hibari. Gokudera replies to this with a difficult saying, to which both Yamamoto and Tsuna fail to understand. Gokudera tries to cheer Tsuna up by assuring him that he could live even without being smart. Tsuna thanks him but adds that if he doesn't make this report, he will be dead by Reborn's hands and wonders if Kyoko would be sad if he died. Hearing this, Gokudera suggests another idea: making a huge commotion in school to lure out Hbari, but Tsuna rejects since it would only damage the school. Yamamoto then asks Gokudera what to do since he's the smartest in their grade. Hearing the word grade, Tsuna suddenly gets an idea on how to find Hibari.
Since Ryohei is the same grade as Hibari, Tsuna thinks that Ryohei might know where Hibari's class is. They found Ryohei at the Boxing Club training room and asks him about it. Much to Tsuna's disappointment and surprise, Ryohei doesn't know where Hibari's class is since he's not in the same class as him. Apparently, Hibari is already the leader of Disciplinary Committee ever since Ryohei first entered Middle-School. Reaching a dead end, Gokudera once again suggests his idea of causing a commotion around the school to draw out Hibari. At this time, Hibari finally appears, asking them what are they are doing. However, when Hibari threatens to bite them to death, Tsuna becomes afraid and Ryohei starts to comment that Hibari is very passionate. Ryohei asks Tsuna and the others to join the boxing club. This causes Gokudera to start an argument with Ryohei while Yamamoto instead asks Tsuna to join the baseball club. Tsuna tries to stop them while forgetting that Hibari is still with them until it was too late. Finally losing his patience, Hibari attacks Tsuna proceeded by Gokudera, Yamamoto, and Ryohei who try to separate and defend him.
Afterwards, Tsuna, who's in the school hallway, is about to go home while commenting that he feels bad to involve the others in his task and ended up being beaten badly by Hibari. As he walks the hallway, he suddenly hears Hibird's voice coming from one of the classroom. When Tsuna takes a peek, he's surprised to find Hibari teaching Hibird to sing the school anthem and have to hold his urge to laugh upon learning that Hibari sang the song himself to teach it. However, when Hibird starts to say "I'll bite you to death" and Hibari replies that Hibird had some nerve to doing so, Tsuna can no longer control himself and bursts out laughing, exposing his position to Hibari. Hibari demands Tsuna to come out or he will be the one to go there. Tsuna quickly reveals himself and apologizes that he's only taking a look. Shockingly, Hibari lets it slide since Tsuna isn't crowding and says he at first thought Tsuna was like the other "small animals" that he knew but Tsuna suddenly started to thrash about and beat up his enemy. Tsuna laughs nervously as he replies in mind that it's because of Reborn's Dying Will Bullet. Curious about which is the real Tsuna, Hibari wants to test Tsuna's power and brings out his tonfas. Tsuna immediately turns down the offer and runs away but then thinks that he never once thought that Hibari could make such a gentle face.
Once Tsuna is not around, Reborn thanks Hibari for helping him out. Hibari replies it's no problem since Reborn is the one who asked. Hibari questions why would Reborn wanted him to walk around school and why Tsuna and the others are doing crowding around him, believing that they want him to bite them to death. Reborn replies that it was necessary since it won't be challenging if they could do the homework easily. Hibari then comments that he doesn't like being used and warns Reborn not to think of using him. Reborn then replies that he knows and states that Hibari has been a lone wolf since birth and that's why Tsuna needs him. Hibari says that it has nothing to do with him since he hates crowding. As he leaves, Hibari says to train Tsuna a little more since it won't be fun to bite him to death now, which Reborn answers that it won't be easy to bite him to death since he's Tsuna's tutor. Hibari leaves with Hibird saying that Hibari is having fun. The story ends with Hibari musing aloud that he's indeed having fun and from now on, something interesting would happen.