Yu-Gi-Oh Forbidden Memories, known in Japan as Yu-Gi-Oh! True Duel Monsters: Sealed Memories is a video game based on the Yu-Gi-Oh! manga and anime series.
The game takes place in Ancient Egypt. The players play the Yu-Gi-Oh! Trading Card Game alongside characters that appear in the series.
One night, Atem escapes Simon Muran, his tutor and advisor, to visit the dueling grounds, where he mets up with Teana and a few villagers. After some games, Teana tells him of a festival occurring in the Plaza, and they leave to see it. They watch the mages march around a shrine, holding flags, and Teana comments that the ceremonies are starting to seem darker, assuming that it is the work of the "detestable" high mage Heishin, a sorcerer who leads a group of independent high mages.
Teana spots Jono dueling, and greets him just as Jono's opponent, Priest Seto, defeats him. Priest Seto mocks Jono's ineptitude in dueling, and Jono and Teana tell Seto that Atem could easily defeat him. Seto and Atem are about to duel when one of Heishin's aides tells Seto that Heishin requests his presence. Seto agrees to duel Atem later at the dueling grounds.
Jono, Teana, and Atem return to the grounds, where Atem has a quick Duel with Jono and defeats him. Seto returns, flanked by aides, and duels Atem, putting on quite a display of ability before Atem claims victory. Seto recognizes that Atem is the prince and says he will meet Atem again.
Atem leaves and returns to the palace and is herded off to bed by Simon Muran. As Muran walks away, a guard tells Muran that Heishin has invaded the palace, wielding some sort of strange magic. Muran starts looking for him and finds Heishin destroying the stone columns of a walkway. Heishin confronts Muran and tells him that he has discovered the Dark Power, and uses the Millennium Rod to blast Muran away. Meanwhile, a servant wakes Atem and tells him to run, just as Priest Seto captures her and his aides take her away. Seto tells Atem that Heishin holds the King and Queen captive, and that to run away would result in their execution. Seto then demands the Millennium Puzzle in exchange for a getaway. Atem refuses, and Muran runs up behind him, looking beaten and weak, carrying the Puzzle and telling him to run. Atem runs, but Heishin corners him, and forces him to Duel for the fate of the Puzzle. However, Heishin defeats Atem (the player will continue to duel Heishin until he or she loses), and Muran tells Atem to shatter the Puzzle, even attempting to subdue Heishin. Atem smashes it, and Muran uses some magic to seal himself and Atem into the puzzle.
Muran tells Atem that his soul is now locked inside the puzzle, and that the only way to release it is to reassemble it. Muran tells Atem to rest, assuring him that someone will eventually complete it.
KC Cup! The Gathering of the 8 Millennium Items
After defeating the preliminary rounds by dueling and defeating Rex Raptor, Weevil Underwood, Mai Valentine, and Bandit Keith, he takes a break. Between the preliminaries and the finals, Yugi and Joey are talking when Yugi spots Shadi, and tells Shadi about the dream. Shadi tells Yugi that the person from the dream is his doppelganger and is named Yami. He suggests that Yugi meet him, through his Millennium Key, and transports Yugi into the Puzzle. Yugi meets Atem, and Atem mentally tells Yugi that he wants to return to his own world. Atem gives Yugi six blank cards and disappears. After waking Shadi asks what happened, and Yugi shows him the cards, but neither of them can deduce what their purpose is.
Joey informs Yugi that the finals are about to begin, and they depart. The first finalist is Shadi, and after Yugi defeats him, the Millennium Key and Scales are forced into the blank cards. Shadi theorizes that the Millennium Items were drawn together so that Yugi could acquire all of them.
Yugi then proceeds to defeat Yami Bakura, Pegasus, and Isis to acquire their items. In the last round of the finals, Yugi faces Kaiba, who possesses the Millennium Rod. Yugi defeats Kaiba and unites all of the Items, which allows Atem to travel into his Egyptian past.
Return to Egypt
Simon Muran awakes Atem in the puzzle, and theorizes that the boy, Yugi, is a representation of the future of Atem. Muran then tells Atem of the current situation. Heishin and the High Mages have taken control of six of the Millennium Items, and rules over the Metropolis. He expands his kingdom by constructing shrines guarded by the five High Mages: Martis, Secmeton, Atenza, Kepura, and Anubisius. Each shrine contains one of the Items, while the Millennium Rod is guarded by Heishin and Seto. Muran warns Atem that the way to defeat them is to find the Forbidden Ruins, and passes away.
Atem is transported back to the Shrine of Glory, which is abandoned. He then travels into the old city, and ventures into the old dueling grounds, which are destroyed. Jono sees him and is jubilant that he survived, and brings him back to the new dueling ground, where he is reunited with Teana and the other villagers, who are hiding underground. Jono tells Atem how the Mages destroyed the card shop and dueling grounds because the villages couldn't locate him. Everyone is relieved that Atem survived, and Jono briefs Atem on the political situation, and how the Mages, led by Heishin, govern the land from the Vast Shrine of Darkness.
Atem leaves and visits the old palace, which is completely destroyed. He meets a Mage Soldier inside, who Atem defeats in a Duel and starts searching the room. He finds a map that depicts an area known as the Forbidden Ruins. He travels to the Valley of the Kings, where he meets the tomb keeper, Sadin. Sadin takes the map and directs him to the Forbidden Ruins, where Sadin points out a map and drawing on opposite walls. After viewing the drawing and ascertaining nothing, Atem looks at the Map while Seto sneaks up behind them and tells them that the Map reveals the location of the High Mages and the Millennium Items. After Seto urges Atem to defeat the High Mages, Sadin yells at him to leave and advises Atem to proceed with caution, since Seto is an enemy and any positive action on Seto's part could be equally dangerous.
Gathering the Millennium Items
After defeating two of the High Mages, Atem decides to take a break at the Hidden Dueling Grounds, and discovers that Teana was kidnapped by Seto. Atem and Jono head to the Dark Shrine, which is unguarded, and storm the building to discover a labyrinth guarded by a Labyrinth Mage. Atem duels and defeats him, and tries to navigate the labyrinth. Depending on how the player navigates, he may or may not face more Labyrinth Mages.
After passing the maze, they find Seto and Heishin with some aides, holding down Teana. Heishin briefly contemplates the existence of the Prince and the Puzzle, and commands Seto to duel Atem and secure the Puzzle, which would be Seto's reward for victory. Seto drags Teana into a secret room and duels Atem, using incredibly strong monsters and strong magic cards before finally losing to Atem for the 2nd time. Seto gloats, stating that the High Mages won't stand a chance against Atem and departs. Teana thanks Jono and Atem for the rescue, and as they travel back to the Hidden Dueling Grounds, wonders why Seto was gloating after his loss, remarking that he "seemed to have a different agenda", while Jono tells Atem to be cautious as they part ways.
Atem finds and defeats the remaining High Mages, gaining a total of 6 out of 7 Millennium Items. Seto then sneaks up behind Atem again and tells him to defeat Heishin by accessing the now unguarded Dark Shrine. After returning to the Hidden Dueling Grounds, the villagers and Jono and Teana congratulate Atem on his victories and hope for a better future.
He then heads for the Dark Shrine located north of the dynasty. Seto shows up in the grand hall, and shows Atem a hidden door that leads directly to Heishin's throne. Seto also warns Atem that Heishin is guarded by mages who have sworn to defend Heishin to the death. Atem passes through the door and is accosted by Neku and Sebek, whom he duels and defeats on a Darkness terrain. Finally, Heishin enters and climatically duels Atem for the second time. Atem defeats him and Heishin is promptly knocked unconscious.
The Forbidden Ruins
Seto enters the room brandishing the Millennium Rod, stating that all of the Items have been gathered in one place, and should be brought to the Forbidden Ruins. Seto finally reveals his hand, stating that he only encouraged Atem to gather the items to save Seto the trouble of doing it himself. Seto then pushes a false stone, revealing a hidden chamber with a statue with the DarkNite.
Seto then challenges Atem a duel. Atem defeats him. Just as Atem is about to decide whether or not to keep or destroy the Items, Heishin appears, grabs Seto, and motions a sword at his neck, threatening to kill Seto if Atem fails to hand over the Items. Atem reluctantly gives them to Heishin, who places them in the statue, causing the Darknite to be summoned. Heishin commands DarkNite to obey, but DarkNite refuses, and since Heishin lacked the Item to prove his authority, Darknite locks him in a card and incinerates him.
Just as DarkNite is about to do the same with Seto and Atem, Atem shows DarkNite the cards Yugi used to acquire the Millennium Items, proving that they had them (or did at one point). DarkNite agrees to duel Atem for his survival, under the conditions that DarkNite departs if Atem wins. Atem defeats DarkNite, but DarkNite does not uphold his end of the deal and transforms into Nitemare.
Nitemare challenges Atem to another Duel. Nitemare is finally defeated.
Seto escapes and is never seen again. Atem orders the Forbidden Ruins buried, and claims the rightful throne, ruling Egypt as a great king.
This game plays differently to the TCG, because it uses prototype rules that were originally being considered when the card game was first being adapted from the manga. Many rules such as Tribute Summoning, Effect Monsters and the need for "Polymerization" to perform Fusion Summons are not present. As for Ritual Spell Cards, they demand specific tributes (For example, when "Zera Ritual" is activated, one must have a "King of Yamimakai", a "Ryu-Kishin Powered" and a "Wicked Dragon with the Ersatz Head" to offer them as tributes and finally summon "Zera the Mant"). Once a Ritual Monster is created, it is Normal Summoned like all other monsters in the game.
The Equip Spell Card equip conditions are also very different in this game, most of the time being based on the type,artwork and the flavour text of the monsters. For example the card "Dark Energy": whilst this card only works only on Fiend-Type Monster Cards in the TCG, in this game this card works on every Zombie-type monster, and various other specific monsters cards like "Jirai Gumo". Their primary guardian stars will also tell a lot about the monster's ability to be equipped with certain cards. For example: All monsters whose first guardian star is Mars ♂, except "Thousand Dragon" can be equipped with "Salamandra" and in most of the cases "Invigoration". Monsters with the guardian star Mercury ☿, except "Gaia The Fierce Knight" can all be equipped with "Dark Energy", "Black Pendant" and/or "Sword of Dark Destruction", and almost never can be equipped with cards like "Book of Secret Arts" or "Legendary Sword".
The card "Invigoration" works on any FIRE Monster Card such as "Flame Swordsman and "Flame Ghost, as well as Thunder and Rock cards like "Boulder Tortoise", but also works on some other monsters like "Change Slime " and the already mentioned "Jirai Gumo "
The card "Legendary Sword" doesn't work on all Warrior-Type Monsters. It works with some Warriors, and can also be equipped to other monsters like "Bladefly, Cockroach Knight", "Tiger Axe" and "Gatekeeper", since they're Warrior-like monsters. "Sword of Dark Destruction " works on all DARK Warrior-Types, some non-DARK Warriors and in monsters like "Zombie Warrior ", "Skull Knight ", "Garoozis " and "Magician of Black Chaos".
The card "Book of Secret Arts" doesn't work on all Spellcaster-Type monsters, but does work with Fairy-Type monsters, and sometimes works with certain specific monsters such as "Psychic Kappa", "Spirit of the Books", "Sea King Dragon" and "Sengenjin".
Unlike in the TCG, after a Equip Spell card is equipped to a monster, the equip card does not stay face-up on the field. The card disappears and the monster permanently gains 500 ATK, except in the case of "Megamorph" where the monster gains 1000 ATK instead. Equip spell cards can also be combined with monster cards in the hand to apply their effects, similar to monster fusion.
There is no Extra Deck, Graveyard, nor a banished zone in this game. Any monster that would be normally be a monster placed in the Extra Deck (for example a Fusion Monster) is a Normal Monster in this game and placed in the Main Deck. If a card leaves the field, it simply disappears for the rest of the game. It is also possible to Fusion Summon other Spell/Trap cards by fusing a Spell/Trap with another Spell/Trap or a monster. For example, you can obtain an "Eternal Drought " by fusing an "Umi with "Mystical Moon or "Dark Hole", and a "Harpie's Feather Duster" by fusing any combination of two cards from copies of "Harpie Lady " and "Harpie Lady Sisters"; or by fusing "Machine Conversion Factory" or "Bear Trap" with certain cards that have feathers featured in their artwork.
The following background music is played during the game. The names listed are unofficial.
- "Main Menu"
- "Input Name Menu"
- "Build Deck Menu"
- "Library Menu"
- "Password Menu"
- "Free Duel Menu"
- "Free Duel"
- "Poly Mode"
- "Simon Muran"
- "Card Shop"
- "Egyptian Duel"
- "Town Plaza Festival"
- "Heishin's Invasion 1"
- "Heishin's Invasion 2"
- "Inside the Puzzle"
- "Modern Times"
- "Tournament Announcement"
- "Modern Card Shop"
- "Preliminary Face-Off"
- "Preliminary Duel"
- "Shadi's Message"
- "Finals Face-Off"
- "Finals Duel"
- "Seto Kaiba Face-Off"
- "Seto Kaiba"
- "Seto Kaiba Poly Mode"
- "Egypt in Ruins"
- "Valley of the Kings"
- "Forbidden Ruins"
- "Seto's Betrayal"
- "Desert Shrine"
- "Forest Shrine"
- "Meadow Shrine"
- "Mountain Shrine"
- "Sea Shrine"
- "Vast Shrine"
- "Dark Shrine"
- "Sebek and Neku"
- "DarkNIte's Arrival"
- "DarkNite and Nitemare"
- "DarkNite and Nitemare Poly Mode"
- "Egypt Restored"
- "Ending Credits"
Japanese promotional cards
International promotional cards
- Complete Card List: List of Yu-Gi-Oh! Forbidden Memories cards