Capital invested in Lagos location (4)
I believe the answer is:
oslo
'capital' is the definition.
(capital of Norway)
'invested in lagos location' is the wordplay.
'invested in' indicates the answer is hidden within the clue.
'OSLO' is hidden in the letters of 'lagos location'.
(Other definitions for oslo that I've seen before include "European capital in go-slow" , "Scandinavian city" , "City in Norway" , "Nordic capital" , "where Ibsen lived under another name" .)