During the final event of the Grand Magic Games, Gray is tasked with beating Rufus, which is the key to Sabertooth's fall. But it seems to be a one-sided battle as Rufus uses his Memory Magic to make new magic, as well as causing Gray to forget his own!
...but Juvia believes in Gray-sama! 
So I'll follow Number One's plan.
لكن جوفيا تثق بغراي-ساما! لذا سأتّبع خطّة الزعيمة الأولى...