During P.E, Tsunayoshi Sawada is hit by the ball on the head and leaves to grab it while his classmates continue playing. As he grabs the ball, it suddenly levitates and Tsuna sees a kid standing in front of him. The kid seems to be ranking Tsuna on his athletic abilities and begins to write it on an enormous book. Suddenly, the kid notices that Tsuna is there and happily approaches him, seeming to know who he is. However, a group of men arrive and the kid runs for it before introducing himself. Later at home, Tsuna begins to tell Reborn about the kid and is surprised to see Reborn covered yet again by insects. Reborn, however, tells Tsuna that a guest is there to see him and Tsuna is surprised to see the kid from earlier.
The kid tells Tsuna that the men that were chasing him are Mafia and begs Tsuna to help him since according to his ranking, he is the first one with the inability to turn down requests. Reborn then introduces Tsuna to the kid, calling him Futa, an informant who is able to make incredibly accurate rankings. Reborn continues to explain that Futa's rankings are very valuable to the Mafia and that whoever gets the book is able to grasp the world, causing Tsuna to conclude that that is the reason why Futa is being chased. Futa continues to beg for Tsuna's help and reveals that Tsuna is also number one on the list of bosses who lack ambition. Reborn also tries to convince Tsuna, and Tsuna reluctantly accepts, causing Futa to jump with joy.
Reborn then points out that the men chasing Futa are already outside. Tsuna plans to get his mom to get rid of them but stops when Futa reveals that they belong to the Todd Family, the seventh Mafia Family for bloodlust and that one of the men, Paolo, is ranked 55th out of 86,000 in terms of strength. Tsuna and Futa decide to leave the house using the back door but this plan fails when Lambo and I-Pin try to surprise the two, causing the men to go after them. As the Tsuna runs for it, he realizes that Futa is missing and that he is the one being chased. The three men begin to interrogate Tsuna about Futa's whereabouts when Futa arrives and uses his ranking power to make the three fight each other. As the three fight, Tsuna tries to get Futa to run but Futa refuses, wanting to write down what he just ranked. However, the three stop fighting and approach the two. Reborn shoots Tsuna with another one of his Dying Will Bullet's giving Tsuna the strength to protect Futa. As Futa watches Tsuna fight, he realizes that his rankings turned out to be inaccurate and asks Tsuna if he can stay with him, a request which Tsuna is not able to refuse...