Head off later and find our theme (2,5)

'head' is the definition.
The answer and definition can be both to do with motion as well as being verbs in their base form.
Maybe you can see an association between them that I can't see?

'later and find our theme' is the wordplay.
I cannot really understand how this works, but
'later' could be 'after' (I've seen this before) and 'after' is found in the answer.
The remaining letters 'go' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...

'off' is the link.

Can you help me to learn more?