On the next floor (8)
I believe the answer is:
upstairs
'on the next floor' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for upstairs that I've seen before include "in one's mind ..." , "On a higher floor" , "at the next level" , "Mentally (colloquial)" , "In the top half of a house" .)