Last two men and girl to follow (5)
I believe the answer is:
ensue
'to follow' is the definition.
(ensue can mean to follow or happen as a result)
'last two men and girl' is the wordplay.
'last two men' becomes 'en' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'and' means one lot of letters go next to another.
'girl' becomes 'sue' (girl's name).
'en'+'sue'='ENSUE'
Can you help me to learn more?
(Other definitions for ensue that I've seen before include "Result in a particular way" , "Proceed" , "succeed" , "Come next" , "Come to pass" .)