Fate/stay night - Season 1 Episode 15 The Twelve Trials The Holy Grail War Begins!
Overview: Archer has been defeated by the unbeatable Beserker and now Shirou, Saber and Rin are trying their best to escape the same fate. They are able to find shelter to bide some time, because Shirou has to find a way to replenish Saber's mana while Ilya looks for them. With Archer's sacrifice, Rin is that much more determined to get out of this alive and comes up with an elaborate plan. The beginning of a fight between Saber and Berserker commences.