Rare Cards have Vanished! The Invincible RookChessmon

Synopsis
Hiroya strives for the top ranking in the card game Sea Monster Cards, but he's not faring well without any strong rare cards. Then he meets KnightChessmon, a Digimon who promises to grant his wish. Later, Tagiru and his friends hear rumors of kids being dragged to another world where their rare cards are stolen. Suspecting a Digimon's involvement, they head to a card game tournament to find the truth...

Hiroya is playing the Sea Monsters game when he is facing an opponent with Orca Blue, which has an attack power of 10,000. He uses Flying Fish Yellow, but Orca Blue defeats him and he knew that he wouldn't have won. Kazumi, Shintarou, and Teppei kick him out of his seat. Hiroya goes home and wants to become stronger, and while waiting for the light, a cat pops out of the bush, and he is sucked into. As he ponders at where he is, he hears a voice. Hiroya backs away and finds a small Digimon and moves back in shock, and the Digimon,, tells him he will help him become stronger.

In a park, is busying spinning a basketball when  tells him its dangerous to do it. Tagiru loses balance and drops the basketball, and as he grabs it he apologizes to three kids for accidentally disturbing them. Kazumi complains on how is card was Octopus Yellow, and Shintarou complains on the card he got, Squid Pink, which he already has. Tagiru wonders why octopuses are yellow and squids are pink. Ewan tells him that they are monsters in a popular card game. Kazumi teases Hiroya for still being in the four-digit ranks and he tells the three he's already in the two-digits.

The three are surprised and wonder if he's joking and then see his rare cards. Hiroya then leaves, while Ewan is suspicious of his motives. Teppei is worried about the rare cards Hiroya has due to a dangerous problem. Shintarou remembers that players with rare cards were sucked into a strange dimension with all of their rare cards taken away. Tagiru and Ewan suspect that a Digimon is behind the taking of their cards.

Somewhere in the city, three kids are crying that some "monster" took their rare cards from them and how they spent a long time getting them. Tagiru meets up with Ewan and. Tagiru asks the two why they're crying over some cards, and Ewan tells him that for those playing the game, it is important for them. After the three decide to help them, Tagiru decides to collect rare cards in order to lure the Digimon to them. Mikey and Ewan tell him that they're rare and hard to come by, so the three decide to go to a Sea Monster gaming area in hopes of finding the Digimon.

In the Sea Monster Card Battle Tournament, Ewan explains to Tagiru that many people who use rare cards come to this tournament. After Ewan explains to Tagiru how the game is played, Tagiru spots Hiroya. Megane tells him he'll show the true power of a real ranker. The two use their cards to fight each other, with increasingly rarer cards being used by Megane. Megane wins the match and leaves the building. As he passes through some televisions, they digitize and drag him into DigiQuartz. Xros Heart soon pursues him into the DigiQuartz.

Megane wonders where he is when KnightChessmon appears, telling him he will take his cards away. He attacks him, and then blows his cards away. A masked boy grabs the cards, delighted that he has even more rare cards. Xros Heart finds the boy and presume he's making the Digimon steal cards. Tagiru reloads, who attacks KnightChessmon. KnightChessmon dodges his attack and accepts Gumdramon's challenge and easily wins. The masked boy tells him to retreat for now since they have the rare cards. Meanwhile, Megane is crying over the cards that were stolen from him.

In Hiroya's room, Hiroya is delighted with the amount of cards he now has, and thanks KnightChessmon for them. He is then transferred into DigiQuartz, and KnightChessmon is happy. Hiroya comments on how hes now the tenth top player, and how he wants to be the number one player. A dark aura emits from Hiroya, and KnightChessmon takes in the aura for himself. KnightChessmon agrees to help him and chuckles.

Back at the shop, Tagiru is upset how he wasn't able to catch KnightChessmon. Mikey asks Ewan if he knew who the masked boy was. At the park, Teppei is amazed at how Hiroya is skyrocketing through the rankings and how much rare cards he has. As Hiroya leaves, Ewan asks him if he really wants strong cards. He then tells him that if he just has strong cards, it loses the value of having fun with the game. Ewan walks over to him and tells him to stop using KnightChessmon to get rare cards, which shocks Hiroya, and that it doesn't show his real strength. Hiroya makes up a lie saying he doesn't know what he's talking about and leaves.

In DigiQuartz, the masked boy takes another card from another player. The dark aura emits from Hiroya again, and KnightChessmon takes in the aura. KnightChessmon grows larger and slide evolves into a black version of himself. Hiroya looks back and asks him that he's changed greatly and grown stronger. KnightChessmon tells him he's eaten his greed, and Hiroya wonders what he's saying. KnightChessmon realizes his mistake and covers it up saying if he wants even more stronger cards, reminding him he's close to becoming the number one player. Hiroya wants them badly that the aura emits again and KnightChessmon takes it in.

Back at Hiroya's room, Hiroya uses his acquired rare cards, Orca Gold, Shark Platinum and Whale Diamond, which wipe out his opponent's cards. A message tells him that he has won and he is now the number one player. He is then taken back to DigiQuartz and tells KnightChessmon of his accomplishment. KnightChessmon asks him what it's like, and he tells him its the best, so the aura emits again. Hiroya notices the aura and he begins to get older. KnightChessmon digivolves into.

RookChessmon explains that his greed allowed him to digivolve into his current form. He also tells him that he doesn't have any more greed, he is going to move to another child to grow even stronger and leaves. Hiroya wanders around trying to find him, and ends up bumping into Megane and RookChessmon. RookChessmon attacks Hiroya and takes his cards, giving them to Megane. He later absorbs the greed from Megane for himself.

In the Real World, a bony Hiroya is in shock. The three boys decide to take his cards and realize that they're loser cards and leave. Ewan asks Hiroya if there's any problem, and he tells him that RookChessmon went to another boy since he's eaten all the greed from him, and stole the rare cards he stole from other players. Mikey realizes that he was the masked boy and that RookChessmon is targeting the players one by one. The three leave in a rush, but Ewan stops and looks at Hiroya before leaving.

In the same building, which is then taken to DigiQuartz, a bony Megane is seen while another child is delighted to have his rare cards. RookChessmon is pleased, but Xros Heart tells him they won't let him do it anymore. Ewan reloads, causing RookChessmon to doubt if he will be a challenge against him. RookChessmon attacks, having the upper hand against them. Damemon attempts to attack him, but RookChessmon isn't affected and plows through the buildings, explaining that his offense has increased by a hundredfold by taking the greed of children for himself.

Tagiru reloads Gumdramon and digivolves him into Arresterdramon. Arresterdramon attacks but is deflected away, and uses his best attack against him. RookChessmon is barely hurt and plows through Arresterdramon, sending him back into Gumdramon. RookChessmon also tells them his defense has increased greatly and that he's the strongest being alive. Ewan is worried with RookChessmon's strength, and Hiroya asks him if its impossible to beat a strong opponent. He later tells him that what he said earlier wasn't false and that by collecting strong cards, he overlooked the fun of the game and his real strength wasn't shown. Ewan then realizes that they should do combining attacks to defeat RookChessmon.

Ewan asks Tagiru to reload to stop RookChessmon from using his "Stronghold" attack. Blossomon digs into the ground and as RookChessmon is about to attack, Blossomon attaches his vines onto his feet, preventing him from moving. As RookChessmon is about to fire to get the vines off him, Ewan tells Mikey to reload, and Starmon and his group of Pickmon appear in a dazzling shine, creating an eyesore for RookChessmon. Damemon uses his "BooSt Attack" to distract him, causing RookChessmon to fire wildly, hitting Starmon and Pickmons.

Ewan tells him that his arrogance is his weakness. RookChessmon attacks Damemon, who is falling midair but he falls down fast enough, causing RookChessmon to realize his mistake and his attack hits himself. The smoke clears and RookChessmon is upset that his defenses are ruined. Mikey and Tagiru withdraw their Digimon and reload and Gumdramon. The three Digimon attack RookChessmon's ruined defenses, defeating him. Ewan then collects and captures RookChessmon's data. A stunned Hiroya watches as his skin returns to normal.

Back in the Real World, Hiroya apologizes and that having strong cards made him believe he was strong. After watching their fight, he realizes what true strength actually is. He thanks Ewan and decides to give back the rare cards RookChessmon returned, apologizing to the people he hurt for his horrible actions. Ewan asks him if they would like to play the game one day, and he agrees to. Tagiru asks he can also play, but Hiroya tells him after he remembers the rules. An upset Tagiru believes that they're making fun of him.

Digivolutions
(Number indicates order of occurrence.)

Quotes
"I can't believe I got beaten by the likes of this bunch!"
 * —RookChessmon's arrogance, right before his inevitable downfall.