Fate/stay night - Season 1 Episode 19 The Golden King The Holy Grail War Begins!
Overview: Saber's fight with Assassin and Shirou's fight with Souichirou reaches its climax. Souichirou shatters Shirou's blades again, sending him flying down to where Rin and Sakura are and it is upto Saber to defeat Assassin and make it down in time to save everyone. With Saber still affected by Caster's Noble Phantasm Rule Breaker, she isn't able to defeat Caster when all of a sudden their fight is interrupted by an unknown Servant. It seems that Saber is familiar with this Servant, but it turns out he's the eighth Servant in this Holy Grail War.In light of the appearance of the eighth Servant, Saber finally reveals to Shirou the shocking events of the previous Holy Grail War.