"The Pack, Part 1", known as "Yuma and Shark - Scar-Filled Tag Duel" in the Japanese version, is the eleventh episode of the Yu-Gi-Oh! ZEXAL anime. It first aired in Japan on June 20, 2011 and in the United States on February 18, 2012.
After his loss to Shark, YumaDuelsBronk without using "Numbers". Yuma is down to 600 Life Points and Bronk Special Summons "UFO Turtle". Yuma attacks it with "Gagaga Magician". Tori and Caswell watch on. Caswell muses that he doesn't understand Yuma's personality - if he lost as badly as Yuma did to Shark, he wouldn't be back on his feet so easily. Bronk activates his face-down "Rush Recklessly", increasing the ATK of his monster by 700. Caswell comments that Yuma is a person who has no pride. "Gagaga Magician" is destroyed and Bronk wins. Caswell reveals that he's now lost to Bronk twenty times in a row, while Astral curses. Yuma wants to Duel again, and Bronk is surprised. Yuma says he has to if he ever wants to become Duel Champion and tells Bronk to come at him again. Bronk walks off, saying he can't do this anymore. Yuma challenges Caswell instead. Tori chases after Bronk, telling him to wait. Bronk says he didn't think Yuma would be the type of person to break a vow like that - he used a "Number" against Shark despite saying he wouldn't. Tori says that's only because Yuma is an idiot, and Bronk says he already knows that. He always knew Yuma was an idiot and full of himself, and he was fine with that. But Yuma wasn't someone who would go around telling lies. Bronk runs off (in the dub, Tori says that Yuma got carried away but Bronk scolds her by saying that there is a difference between breaking a promise and get carried away and adds that nobody should break a promise because they are in danger of losing).
At the run-down arcade, some of the thugs are Dueling. One of them, Weasel, asks Shark why he doesn't play with them once in a while. Shark ignores him and walks off. Later, Weasel goes to Scorch and Chills, asking them to do something about Shark and his arrogance. Scorch tells him he doesn't get it - they don't consider Shark to be one of them. Chills reveals that they want to turn Shark into an underground Duelist, as he's already fairly famous in the Dueling world. If they do that, they can sit around and get paid for nothing.
On the way to school the next day, Yuma catches up with Bronk, asking him if they can Duel today. Bronk simply says he can't Duel with him anymore and rides off on his hoverboard. Yuma shakes it off, saying there are plenty of other people to Duel with anyway. Astral appears and tells him that it doesn't matter who he Duels with right now. He says that Yuma would usually at least use basic strategies in his Duels, but he isn't even doing that anymore - he's simply recklessly attacking over and over again. Yuma asks what he means and Astral responds that Yuma is irritated about losing to Shark. Astral says that Shark is indeed a very talented Duelist, but that is not the only reason he won. Yuma again asks what he means and Astral says that Shark thoroughly studied Yuma's Deck and found the weakness of the "Numbers". But Yuma really knows nothing about Shark. Yuma thinks back to when Bronk speculated that something happened to Shark at Nationals.
Back at the arcade, Scorch and Chills talk with Weasel again, as Shark eavesdrops from outside the door. Weasel asks if they're serious and Scorch says that of course they are - they won't get another chance like this. They tell Weasel to look at the TV news broadcast. The reporter reveals that the centerpiece of the new museum exhibit is a super rare Deck of cards that has been lost for quite a while. The top card shown is "Chaos End Ruler -Ruler of the Beginning and the End-". The reporter states that the Deck was recovered by chance from a package shipped to the museum. Chills is excited, saying he really wants that Deck. Weasel asks if they're sure - robbing the museum would be dangerous, they could get thrown in jail if caught. Chills says they don't care about that and that Weasel always used to say they needed to do something big. Scorch says they have no need to worry - they have "these guys" on their side. Both brothers hold up a card as the number "61" appears on Scorch's shoulder and the number "19" appears on Chills's elbow. He says there's no way they'll be caught and Scorch adds that the power of these cards protects them. Weasel seems hesitant and Chills asks him what's wrong. Chills bursts out of the room and sees Shark. He says that since Shark heard everything, he'll give them a hand with the job. Shark says that's no problem and Scorch says it's decided - they'll go tonight. Weasel talks with Shark in private, and is weeping, believing it's all over for both of them. Shark tells him to leave town while he still can. Weasel asks why Shark would let him run and Shark yells at him to just hurry up and go.
Yuma is in the school library on a computer, but finds he can't access the information he wants. Tori arrives and says that Yuma being at the library is a very rare sight. She pushes him over and starts typing, asking him why he's looking up the National Duel Monsters Championship. The article calls Shark the "tarnished champion candidate". They read that Shark was disqualified for peeking at his opponent's Deck before a Duel began. Elsewhere, Weasel runs through the streets. After school, Yuma and Tori speak again, and Tori says it's hard to believe that's why Shark was disqualified. Yuma says it can't be true - the Duel he had with Shark was not with the type of person who would cheat like that. Weasel runs up to them and explains the situation. He says that ever since Scorch and Chills obtained "those cards", they haven't been acting like themselves. Astral appears, speculating it's "Numbers". Weasel says he's sure the brothers plan to place all the blame on Shark for the theft. Yuma begins to run off, but Tori tells him to wait - he shouldn't meddle in Shark's affairs again. Yuma says the has no choice but go and Tori asks why he would go for Shark's sake. Yuma responds that he isn't - he's going for his own sake. He lied - he may have said the Duel was for Shark's sake, but he only challenged him because he wanted to win. Because of that, he used "Numbers". He doesn't wish to be that type of person.
Chills wonders where Weasel ran off to, and Scorch tells him to forget about it, they'll let Shark take Weasel's role. The three board their motorcycles and quickly drive to museum. They find Yuma waiting for them. He tells them that he won't let them pass this point. Scorch and Chills both glow with a purplish aura as the "Numbers" symbols appear on their bodies and Chills recalls that Yuma is that stubborn kid from earlier. Yuma tells them that if they want to pass, they'll have to beat him in a Duel. Chills asks what he's planning and Yuma says that if they win, they can have "Number 39: Utopia", as he holds up the card. Shark is shocked to see Yuma ante a "Number" and Yuma finishes by saying that if he wins the Duel, they'll leave the museum alone. Scorch realizes that the card is the same as their own, and is surprised to learn that there are more "Numbers". They agree to Duel, knowing the power they have with just the two cards will be increased with a third. Yuma tells them to come at him and Shark asks what's he thinking trying to Duel them two on one. Yuma responds that there's no way he'll let Shark become a card thief. Shark reiterates that Yuma shouldn't get involved with him. Yuma says he can't do that, - Scorch and Chills are just using Shark. Shark says he already knew that they were using him, but that he has no where else to go. Yuma tells him he's wrong - Shark doesn't belong with them. He'll prove it in the Duel. Shark yells at Yuma, asking why he would go that for him. Yuma tells him it's because they're friends.
Tori is with Bronk, trying to convince him to help Yuma. Bronk refuses. Tori tells him that yes, it's true that Yuma lied, but he's now fighting to correct that. Scorch tells Yuma the time to talk is over - and that it's not even two on one - it's three on one. Yuma says that's fine, but Shark walks over and stands next to him. He apologizes to the brothers, but says he'll be siding with Yuma. Chills is shocked he's betray them and Shark tells Yuma he's just sick of the two of them. Chills asks if they're challenging them to a Tag-Team Duel and Scorch calls them idiots - Shark should already know what will happen next. The four set their Duel Disks and Duel Gazers and the Duel begins. Each player begins with 4000 Life Points and the rules of the Tag Duel treat each player (including those on the same team) as opponents for the purposes of card effects. Scorch goes first and Sets a monster. He and Chills laugh as he Sets two more cards. Astral tells Yuma that it looks like the two of them are experts at Tag Duels and urges him to be careful. Yuma says he'll be fine and Normal Summons "Zubaba Knight". Yuma calls for an attack but Shark tells him wait - in a Tag Duel, no one can attack until everyone has had a turn. Yuma ends his turn and Scorch believes they'll have an easy win if their opponent is such an amateur. Chills begins his turn, Normal Summoning "Pompadour Blizzardon" and Setting two cards. They tell Yuma and Shark that they'll regret challenging their invincible Tag Duel combination.
Shark goes next, Normal Summoning "Big Jaws", who appears in a twister of water. He activates the effect of the "Shark Stickers" in his hand, Special Summoning it as a Fish-Type monster was Summoned. Yuma comments that Shark has two Level 3 monster and asks if he's going to go for it. Shark responds by overlaying the two monsters to Xyz Summon "Submersible Carrier Aero Shark" in Attack Position, who bursts from the ground, scattering rubble all over. Yuma is impressed to see a first turn Xyz Summon again. Shark activates the effect of "Submersible Carrier Aero Shark", detaching the overlaid "Big Jaws" to the Graveyard to inflict 400 damage to Scorch for each card in Shark's hand. Astral comments that it's a good move - he can't attack on the first turn, so he went for effect damage instead. "Submersible Carrier Aero Shark" launches four torpedoes at Scorch, whose Life Points drop to 2400. As the smoke clears, Scorch glances at Chills, who activates his face-down "Blizzard Egg Level 5". This lets Scorch Special Summon a Level 5 monster from his hand as he took effect damage. If they have no Level 5 monster, they take 500 more damage. Astral comments its a risky gamble, but Scorch does have a Level 5 monster - "Baggy Pants Lavasaurus", who appears in Attack Position. Scorch then activates his own face-down card - "Flame Egg Level 5" This lets Chills Special Summon a Level 5 monster from his hand since Scorch took effect damage. Again, if he cannot, he'll take 500 damage. Chills Special Summons "Icebergdon" in Defense Position. Astral is surprised that he also had a Level 5 monster, and Yuma is shocked they were able to Special Summon two monsters at once. Chills calls this their "perfect combination" and Scorch says no one has ever beaten them in a Tag Duel. Astral is curious about the complete confidence they have and determines there is something not right with this Duel.
Scorch activates another face-down card - "Glare Level 5", which inflicts 500 damage for each Level 5 monster his team controls. Shark's Life Points drop to 3000, as both Dinosaurs shoot red beams out of their eyes at him. Shark is unfazed, getting up and Setting two cards to end his turn. Yuma is concerned. No one has attacked yet, but their Life Points keep dropping. Shark tells him to calm down if he wants to win. Yuma becomes more serious, realizing that this Duel determines the future of both Shark and himself. They can't lose here. Tori gracefully climbs over the fence to watch the Duel as Bronk falls off of it and Scorch begins his turn. He Flip Summons his face-down monster, which is "Flamesaurus". Bronk is surprised to see a Tag Duel and even more surprised that Yuma is teaming with Shark. The Flip Effect of "Flamesaurus" activates, increasing its own Level by 1 - to 5. He overlays his two monsters to Xyz Summon "Number 61: Volcasaurus", who appears in Attack Position from a floating sphere of lava. Scorch tells Chills they'll show them their true terror now. Scorch activates the effect of "Volcasaurus", detaching an Overlay Unit to destroy an opponent's monster and inflict damage to that player equal to the destroyed monster's ATK. "Submersible Carrier Aero Shark" is destroyed and Shark's Life Points drop to 1100 as "Magma Max" hits. Shark is thrown to the ground and Yuma screams his name. Chills asks if this really a good time to worry about others. Scorch activates "Mag-Max" again, detaching the other Overlay Unit to destroy Yuma's "Zubaba Knight" and drop his Life Points to 2400. Scorch asks if they see their power now and Chills says that Yuma's "Numbers" will soon be theirs, before they both laugh maniacally.
Scorch Flip Summons his Set, "Flamesaurus" (1800/1200), activating its Flip Effect, changing its Level from 4 to 5. Scorch overlays his two monsters to Xyz Summon "Number 61: Volcasaurus" (2500/1000) in Attack Position. He activates the effect of "Volcasaurus", detaching an Overlay Unit to destroy "Submersible Carrier Aero Shark" and inflict damage to Shark equal to its ATK (Shark 3000 → 1100). He then detaches the other Overlay Unit to destroy "Zubaba Knight" and inflict damage to Yuma equal to its ATK (Yuma 4000 → 2400).