Saber faces Assassin while Archer and Caster go into battle against each other! What will be the outcome?

Rin suspects Kuzuki might be the Master of Caster. With the help of a hesitant Shirou, she implements a dangerous plan in a remote location to test out her theory.

Shirou is devastated since he was unable to save Illyasviel. Together with Rin, he is determined to fight Caster and the others. Out of the blue, they are visited by a Servant who is willing to lend a hand!

Shirou's battle with Archer continues. But then an unexpected visitor appears, and new information unfolds.