Season 1 - Episode Guide

The grail war will start eight years later from the birth of Kiritsugu's daughter. Matous and Toushaka family arranged their plans to summon the Holy grail and fulfill their wish. Tohsaka tokiomi made his student Kirei a master for the Holy grail to be as a puppet. Zouken from matous family made his Kariya a master. All the 7 masters then call upon their servants to fight for them to bring the Holy grail home.

Waver has a hard time commanding his Servant Rider (Alexander the Great), as Rider is more interested in how the world has changed since his time and intends to conquer it once he wins the War. Saber has formed a poor opinion of Kiritsugu, considering him cold-hearted, but is surprised to see him have a tender moment with his daughter Ilya. Saber also admits she admires Kiritsugu and Iri's wishes to save the world, as she, too, wishes to save Britain. In Fuyuki City, serial killer Ryuunosuke Uryuu has murdered an entire family except a young boy to summon a demon, but inadvertently calls the servant Caster (Bluebeard). When Uryuu offers the boy to Caster as a sacrifice, Caster pretends to let him go, then kills him with a horrific Cthulhu-esque monster. Uryuu, overjoyed to meet someone as sadistic as him, vows to follow Caster anywhere and becomes his Master. Upon learning the seventh and final Master has been chosen, Kirei orders Assassin to kill Tokiomi, only for Assassin to be killed by Tokiomi's servant Archer (Gilgamesh), while attempting to break into his mansion

Kirei announces his resignation from the war due to Assassin's elimination and is granted asylum by Risei. However, this is actually a ruse by Kirei, Risei and Tokiomi: "Assassin" is not one, but several dozen people. With everyone else believing him out of the game, Kirei can send the Assassins to spy on them without suspicion. Waver informs Rider of Assassin's demise, but the latter is only interested of defeating President Clinton, acquiring his country's military weapons and having a good time. Saber and Iri arrive at Fuyuki City to meet up with Kiritsugu, but decide to tour the city since this is Iri's first time abroad. Meanwhile, Kiritsugu meets up with his assistant Maiya Hisau, who informs him the other Masters believe Iri is Saber's Master and that she has smuggled in the guns they need for the war, including his Contender pistol. As Iri has a good time at the beach, Saber detects another Servant at the harbor. Once there, they encounter Lancer, who challenges Saber to a duel.

Saber and Lancer fight, while complimenting each other on their skills and chivalry. At the same time, Kiritsugu and Maiya are scouting the battle, with Kiritsugu spotting Lancer's hidden Master. As he is about to snipe him, Kiritsugu spots Assassin, who is relaying the battle to Kirei and Tokiomi. Lancer's Master orders him to use his Noble Phantasms, Gae Dearg, the anti-magic spear and Gae Buidhe, the cursed spear that inflicts wounds that cannot be healed. From these, Saber recognizes Lancer as Diarmuid of the Love Spot, while Lancer discovers Saber's identity after using Gae Dearg to temporarily dispel the invisibility spell on her sword. Saber, whose left tendon was wounded by Lancer's Gae Buidhe, is about to give it her all when Rider, who was watching the battle from afar, suddenly rides down to the harbor on his chariot, interrupting the battle.

Rider introduces himself to Lancer and Saber and asks them to join his army, with both declining. Lancer's Master, Kayneth, reveals himself and mocks Waver, but Rider defends him. Soon after, Archer and Berserker join the battle. Berserker, Kariya's Servant, is a Black Knight covered in a fog that prevents all attempts at gauging his strength. Archer attacks Berserker with his Noble Phantasm, Gate of Babylon, but Berserker keeps evading and using Archer's weapons against him. To prevent Archer from exposing his Noble Phantasm further, Tokiomi expends a Command Seal to order him to withdraw from the battle, much to Archer's displeasure. After seeing Saber, Berserker goes after her and his ability to turn anything he wields into a Noble Phantasm is revealed. Lancer defends Saber out of chivalry, but Kayneth uses a Command Spell to force him to assist Berserker. However, Rider incapacitates Berserker and warns Kayneth to withdraw, or he will side with Saber. After Berserker, Kayneth and Lancer retreat, Rider tells Saber he will not duel her or Lancer until their duel is finished. Elsewhere, Caster watches the battle through a crystal ball and thinks Saber is his long-lost love, while Kirei discovers that the church was being spied on by a familiar.

Iri and Saber are driving to Einzbern Castle when they encounter Caster. Caster believes Saber is Jeanne d'Arc, but Saber tells him he is mistaken and drives him away. Returning to his lair, Caster is convinced "Jeanne" has lost her memories. At his hotel, Kayneth scolds Lancer for failing to kill Saber. Lancer is defended by Sola-Ui Nuada-Re Sophia-Ri, Kayneth's fiancee, who is maintaining Lancer's existence by supplying him with mana and has fallen for him due to his magic love spot. When the hotel's occupants are ordered to evacuate, Kayneth realizes Saber's Master has come for them. After making sure all civilians have evacuated, Kiritsugu and Maiya blow up the hotel using explosives. Maiya is found by Kirei, but escapes thanks to Kiritsugu's smoke bomb. When the Assassins inform Kirei, Risei and Tokiomi that Caster and Uryuu have been kidnapping and sacrificing children, Risei is disgusted by their pointless murders and their jeopardising the war's secrecy. In a meeting between Archer and Kirei, the former convinces the latter to spy on the other Masters and find out what drives them in order to discover his own desires.

Risei informs all the active Masters that the war is to be put on hold until Caster, whose killings of children are attracting the public attention, is destroyed, with an additional Command Spell as a reward. In Einzbern Castle, Kiritsugu plans to use the hunt for Caster to attack the other Masters, despite Saber's protests that they should give priority to stopping Caster's atrocities. As Kiritsugu confides in Iri that he would rather escape with her and their daughter and live in peace somewhere, Iri detects Caster arriving from the forest with more children to be sacrificed and sends Saber after him. Saber is ambushed and cornered by Caster's summoned monsters until Lancer appears and joins forces with her. As Iri and Maiya leave the castle, Kayneth, who had survived the hotel bombing thanks to his Volumen Hydragyrum, a giant magical blob of mercury, infiltrates the castle to duel Saber's Master. Kiritsugu evades Kayneth using his Calico M950 and launches a surprise attack with his Contender pistol.

Iri and Maiya are about to escape through the woods until Iri detects Kirei coming their way. Instead of evading him, Iri and Maiya decide to confront him in order to protect Kiritsugu. However, both of them are outmatched. Meanwhile, Kiritsugu is able to wound Kayneth with his Contender pistol. Believing the attack was a fluke, Kayneth decides to increase Hydragyrum's defense even further. Saber and Lancer continue fighting Caster's waves of demonic creatures, which prove limitless due to his Noble Phantasm, his grimoire. Saber manages to clear a path for Lancer, who pierces Caster's grimoire with Gae Dearg, cutting off his source of mana and instantly destroying his minions, causing him to flee. After hiding from an enraged and injured Kayneth, Kiritsugu finally appears and shoots him with his Contender again. Because the Contender uses special anti-magic bullets, Kayneth's Hydragyrum not only fails to protect him, but amplifies his injury significantly. Lancer arrives to save his unconscious master, while Saber rushes to save Iri from Kirei. As Kirei interrogates Iri about Kiritsugu, an Assassin informs him of Saber's approach, leading him to stab Iri before fleeing. Iri survives thanks to Saber's magical healing scabbard Avalon implanted inside her and goes on to heal Maiya.

Kayneth wakes up with his body tied to a bed. Sola tells Kayneth that his Magic Circuits were destroyed by Kiritsugu's bullets and he can never use magic again. At Sola's mercy, Kayneth has no choice but to relinquish Lancer's command to her. Despite Sola becoming his new Master, Lancer wishes to remain loyal to Kayneth, but Sola convinces him to keep fighting with her, using Kayneth's honor as a pretext. Kiritsugu decides to hunt Kayneth down despite Saber and Iri's wishes to stop Caster. Meanwhile, Waver and Rider manage to find Caster's lair, where they are horrified to see the mutilated bodies of his victims. Before setting Caster's lair on fire, Rider kills an Assassin targeting Waver and drives off two more. With Waver and Rider now knowing their secret, Tokiomi orders Kirei to send his Assassins to spy on them.

This episode focuses on Tokiomi's daughter, Rin, and her involvement in the Fuyuki City Kidnappings. Despite her young age, Rin is determined to follow in her father's footsteps as a great mage. With the Holy Grail War starting soon, Tokiomi sends Aoi and Rin away for their own safety. At Rin's new school, several children, including her best friend Kotone, have been kidnapped by the Fuyuki Serial Killer. Wishing to save Kotone, Rin heads to Fuyuki City alone. Using a mana detector gifted to her by her father, she eventually finds Uryuu using a magic bracelet to hypnotize children. Rin follows Uryuu to his hideout, where she is found by him. Rin overloads Uryuu's bracelet with mana, destroying it, incapacitating him and freeing the children from his control. With everyone safe, Rin heads home only to be ambushed by one of Caster's monsters; however, Kariya comes to her rescue and later hands her to Aoi. Kirei, who had been spying on them through Assassin, orders him to continue monitoring Kariya.

Rider and Waver, unexpectedly arrive at Einzbern Castle. Rider declares his intention to have a peaceful discussion with her and Archer on the subject of kingship and the wishes they want the grail to grant. Saber argues a King should serve his people selflessly and wishes to use the grail's power to save Britain. Rider criticises her, saying that Saber's emotional distance from her subjects led to their dissatisfaction and proposes his own ideal, namely that people should serve the king, whose extravagant ambitions inspire them in turn. Their talk is interrupted by the arrival of the Assassins. When they rebuff Rider's offer to join the feast, Rider summons his Noble Phantasm "Ionian Hetairoi," the Armies of Macedonia, composed of his loyal soldiers who also became Servants after their death. Rider and his army easily decimate every single Assassin. With their meeting over, Rider tells Saber he no longer recognises her as a king and departs. A conflicted Saber reveals to Iri that one of her knights left Camelot because he was dissatisfied with her rule.

Thanks to the information provided by the Assassins before their annihilation, Tokiomi and Kirei now know about Rider's Noble Phantasm and decide to let him attack the other Servants first before engaging him. While Maiya transports Iri and Saber to their new headquarters, Kiritsugu reviews his intel about the other contestants' whereabouts. At their new headquarters, Saber points out Iri's odd behavior, which forces her to admit that her powers have weakened. Archer questions Kirei about what he learned by spying on the other contestants and points out that Kirei has shown an unusually large interest in Kariya, despite the minimal threat he poses. From this, Archer concludes that Kirei enjoys seeing the pain and suffering of others. Though initially reluctant to acknowledge his dark nature, Kirei eventually gives in, at which point the Command Spells reappear on his hand, signifying that he is still meant to be a contestant. Since he currently has no Servant, however, Archer hints that he should kill another Master and take over their Servant.

Caster and Uryuu returns to their lair and are dismayed to see their "artwork" destroyed by Rider's fire. Uryuu cheers Caster up by sharing his twisted view that God, who Caster hates the most for Jeanne's death, is just a spectator who enjoys seeing humans do whatever they want. Impressed by his Master's idea, Caster plans a "grand spectacle" for God. Meanwhile, Waver has second thoughts about being a worthy master for Rider, but Rider encourages him to believe in himself. Suddenly, Waver, Rider, Saber and Iri sense magic from Mion River. When they arrive, they witness Caster summoning a giant demonic monster. Rider informs the other contestants and they all agree on a temporary alliance to stop Caster before his monster destroys the city. With Rider leading the vanguard, Saber joins him to give Lancer an opening to use his spears on Caster.