Ep 7. Writhing

Shirou wakes up to find his home in complete disarray from the previous night's events. He meets with Saber, who tells him about Rider, the servant of their enemy, Caster. Shirou goes to school, but discovers that Rin hasn't shown up yet. He decides to search for her, and by chance, runs into Rider. Despite the danger, he tries to follow Rider, but she becomes aware of his presence and attacks. Rin comes to the rescue, and together with Shirou and Saber, they defeat Rider.

Afterwards, Rin and Shirou have a conversation about their respective strategies in the Holy Grail War. Rin reveals that her goal is to defeat Caster, and that she has been following Shirou to learn more about his servant. She also tells him about the rules of the Holy Grail War and how they are enforced by the Church.

Meanwhile, Caster becomes impatient with Rider's lack of progress and decides to take matters into her own hands. She attacks the Church and kidnaps its leader, Kirei. She then summons Assassin, a servant who specializes in assassination.

Saber and Shirou return to his home to find it under attack by Assassin. They are able to fend him off, but not before Kirei is fatally wounded. Rin arrives on the scene and performs a healing spell on Kirei, allowing him to survive.

Later that night, Rin and Saber confront Caster in her lair. Caster reveals that she has been using children to power a magical barrier around the city. She also reveals her true identity as the Greek prophetess Medea. Rin engages Caster in a battle, but is quickly overpowered. Saber steps in to fight, but is also outmatched. Just when it seems like all hope is lost, Shirou arrives on the scene and engages Caster in a fierce battle.

In the end, Shirou is able to summon a powerful sword capable of defeating Caster. With Caster defeated, the magical barrier around the city disappears, but the damage has already been done. Shirou is left with a sense of guilt for not being able to protect the innocent children who were victimized by Caster's magic.

As the episode comes to a close, Rin and Saber both acknowledge Shirou's bravery and skill, but also warn him of the dangers he will face in the future as a master in the Holy Grail War. Shirou is left wondering if he is truly ready for what lies ahead.