House mice on the inside in house (4)
I believe the answer is:
semi
'house' is the definition.
(I've seen this before)
'house mice on the inside' is the wordplay.
'the inside' indicates the answer is hidden within the clue.
'SEMI' is hidden in the letters of 'house mice on'.
'in' is the link.
(Other definitions for semi that I've seen before include "match, the last but one?" , "Partly detached home" , "place" , "important match" , "Connected house" .)