Northbound vampires making attempt? (4)
I believe the answer is:
stab
'attempt?' is the definition.
(to have a stab is to attempt something)
'northbound vampires' is the wordplay.
'northbound' says the letters should be written in reverse.
'vampires' becomes 'bats' (I've seen this in another clue).
'bats' in reverse letter order is 'STAB'.
'making' acts as a link.
(Other definitions for stab that I've seen before include "Sudden sharp feeling" , "Go" , "effort" , "Strike with knife" , "Pierce with a knife" .)