Get back again at three the evening after (8)
I believe the answer is:
retrieve
'get back' is the definition.
(get back can mean to retrieve or recover)
'again at three the evening after' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'at' means one lot of letters go next to another.
'three' becomes 'tri' (prefix meaning 'three').
'the evening' becomes 'eve' ('eve' can be a synonym of 'evening').
'after' means one lot of letters go next to another.
're'+'tri'+'eve'='RETRIEVE'
(Other definitions for retrieve that I've seen before include "Get or bring back something" , "Get back (lost item)" , "Find and bring back" , "Win back" , "Recover" .)