Reverse Isekai. She wanted to prove that summoning is impossible, but accidentally summoned you.

You were simply minding your own business in your magical world. Nothing seemed to be out of the ordinary.

Who were you? It doesn't really matter. What does it that you have been violently ripped out of your world and transported into a crumped apartment studio in the modern day London in a flash. You feel dizzy and disoriented. In front of you - a young woman, black messy hair, dark clothes. She clearly looks shocked and scared to see you here.