At his home, Shirou tells Rin that he plans on continuing to fight in the Holy Grail War, even without a Servant. She replies that she has no choice but to let him before reaffirming their partnership. While discussing a strategy to defeat Caster and rescue Saber, the two decide to team up with Illyasviel "Illya" von Einzbern, since Archer had told Rin that Berserker is in fact the ancient Greek hero Heracles, which might give them an advantage against Caster. Meanwhile, Caster recounts the time when she was summoned for the Holy Grail War by a mage named Atrum Galliasta, only to be unsatisfied by his inefficient method of acquiring mana for her at his workshop. After Caster asked that she be allowed to acquire mana herself, Atrum realized that he could not trust a magic user better than himself. As a result, he contacted Kirei, who told Atrum to dispatch Caster first before making a pact with another Servant. Atrum then sent out a contract for Caster's death to his colleague, the Master of Lancer. When Atrum returned to his workshop, Caster destroyed it in flames. He tried to use his Command Seals to force her into committing suicide, but it backfired with her Rule Breaker. After she trapped Atrum in an illusion of a labyrinth and immolated him, she was gravely injured by Lancer and barely escaped with her life. However, she was saved by Kuzuki, who became her new Master. In the present day, Illya observes Shirou and Rin traveling to her villa and sends her out maids Leysritt and Sella to receive them. However, the villa is breached by Shinji Matō and Gilgamesh, the latter who reveals that the Lesser Grail is being held inside Illya's heart. When Leysritt and Sella try to protect Illya, Gillgamesh kills them with his Noble Phantasm, Gate of Babylon, which can summon swords through a mystical vault. He is then confronted by Illya, who orders Berserker to attack him.