A boxing match is seen with a man named Hayase Tsubasa winning against an old foe who fights dirty. At HQ Masaru shows Yoshino what he believes to be a Digimon case involving Hayase. He says world champions Hayase was intended to fight against have been dropping out of matches. Touma tells Masaru that Hayase would never do such a thing but Captain Satsuma walks in with a needle and says it contains a Digimon signal. This further increases the fighting between Masaru and Touma so Yoshino suggests that all investigate.

Touma catches up with Hayase who is on a run and says he would like to train with him. Hayase agrees only if he is able to keep up. Touma is able to and brings up a fight from four years ago between Hayase and a boxer named Uehara (The man seen fighting with Hayase at the beginning). He recounts how Hayase was at the verge of defeat because of Uehara’s dirty tactics but was able to make a comeback at the cost of permanently injuring his arm which damaged his chances at the world championship. Hayase says he was able to get through the ordeal with the support of his family. Touma asks if there was anything strange about his comeback match and Hayase says no. Touma leaves wishing Hayase luck in his title match.

When Hayase returns to his gym he discovers Masaru waiting with a bunch of knocked out trainers. Hayase ignores him and leaves him to Shiraki, his coach. Shiraki seems to like him and says he doesn’t mind looking after Masaru while he’s at the gym.

Yoshino starts her investigation by posing as a magazine reporter wanting to do an interview with Hayase’s wife. His wife says she wants him to come back safely.

At DATS Satsuma says they have narrowed it down to Hayase, his wife, and Shiraki (one of them is hiding the Digimon). Touma says they should wait and let him look at Hayase’s surroundings once more. One night at his computer he discovers something but doesn’t say what it is. The next day he catches Hayase during his run and asks to spar with him to discover if he is right. Hayase agrees and the two begin to fight. Masaru comes in at the beginning of the second round but Touma drops out after seeing what he needed to and leaves without saying anything to Masaru.

That evening Gaomon asks why Touma has been acting different and Touma says he looked up to Hayase before he got injured. Gaomon realizes he knows who is hiding the Digimon.

Masaru sneaks into the gym at night to see the coach snooping around. Masaru asks him what he is doing and the coach pulls out a bottle of alcohol saying he loves to enjoy himself before a match. The two see Hayase enter and begin practicing in the gym. The coach asks what he is doing and Hayase says he is just practicing before the match. Hayase’s phone rings and it’s his wife saying they have trouble.

Uehara is running in an ally and is attacked by a Togemon. Touma and Gaomon manage to deflect the attack before Uehara is injured. Touma reveals that it is Togemon’s thorns that made Hayase’s opponent’s drop out. He also says the one behind Togemon’s actions is his daughter and she appears. Togemon and Hayase’s daughter run away from Touma and co. until they arrive at the boxing ring. Touma and Gaomon are waiting and Togemon is challenged to a match.

The two Digimon fight and Gaomon says he won’t let cheating ruin the sport that his master loves. Togemon grows in size so Gaomon evolves into Gaogamon and finishes Togemon off.

Touma takes his daughter back to Hayase and tells him what happened. He asks him to forfeit because he will hurt himself in his condition. Hayase says he won’t because he wants to show his daughter how he looks when he fights fair-and-square. Touma is forced to erase Hayase’s memory and Hayase is seen walking into the ring and past Touma, his forgotten biggest friend.