The last thing Arturia Pendragon expected was to summon to another Holy Grail War after destroying the Holy Grail of the Fourth Holy Grail War. She wakes to find that she had be caught by a Pokeball and turned into a Pokegirl by her older sister, Morgan le Fay. Will Arturia be able to free herself before it is too late or will she be transformed into Morgan's slave?

Fem!Shirou and Arthur found themselves in a world eerily similar, but at the same time different, to the fictional world Pokemon. After a series of events, Shirou finds herself transformed into a female Pokeslave, a Pokegirl. It is up to Shirou and Arthur to find clues to reversing Shirou's transformation before either Shirou or Arthur succumbs about their new statuses.