0) Bring 2 bars of elf liquid
1) Bring Momoko with you to the asylum. 2) Banish the ghost 3) follow momoko to a room, speak to her to start the quest. 4) You will get a key to search drawers in reiko hallway and masumi hallway tell. 5) tell her about Kaori 6) buy twice Okonomoyaki from kana's food and (eat the okonomoyaki on the table but DONT EAT the piece of okonomoyaki you get from it) 6) grab UV light and go to Reiko hallway 2.

7) go to the very left of the room and wait until you fully see the portal to enter it. 8) enter it and go foward until you find a room. talk to her, heal her with elf liquid and then you will be promted to give her the piece of okonomoyaki 9) now go beyond the gate and enter a room YTILITU  (UTILITY) where you find another girl. Do the same as with the previous girl. 9) Now... go back slowly to the portal with the girls following you. (I dont know if they die if you leave them, it did not happent to me, but peole say stay out of the shadows and dont leave them alone) Upon returnal, the girls will sprint to the van, thus unlocking Masumi. 

BONUS: 10) return to Momoko, talk to her and press X, you should have another unique animation 11) return to the portal, enter it and Go to the right until you reach the upper floor. Walk left and you will see shadow pass over a window. Reaching the end of the room, you should have already seen her 3 times pass the window, thus unlocking a new Ghost to banish.

EDIT: step 5) and 7) corrected, step 0) added