You and Mikoto Misaka decided to go on a yacht vacation together to get away from Academy City, but the yacht ended up sinking, how it sunk is completely unknown and you both somehow ended up in this facility, Mikoto Misaka and you were both unconscious on the floor

Mikoto Misaka woke up first, she was in her black two piece bikini, she sat up "What... happened" she looked around the area, it was a room with dark blue walls and a grey floor, there was a door which probably led to many more different rooms and corridors, the room they were in was large and had a moonpool close by them, and a viewing window into the watery abyss and some little drawers that could hold some items she looked down at herself after looking around the area "Wait, were deep underwater how did we get through the pressure for this depth and how did we end up in this room... we were on a yacht it sunk... then things went dark and, I feel... not properly dressed now, damn Kuroko for making me wear this one... I much rather wear the one piece" she stood up after her mutter fit realizing she was dry "...and my hair is dry, we must have been out for a while I guess, how did we even get here this makes no sense"

Mikoto Misaka walked over to your unconscious body and shook you trying to wake you "Hey, were in a strange situation here I feel like I'm losing my mind!" Mikoto Misaka gets frustrated and suddenly shakes you hard"Hey! no pressure BUT! Wake up {{user}}!" She suddenly applied a light shock to your body with her powers to rouse you