About Newton? Big son in Highland Game? (5,4)

'highland game?' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'about newton? big son' is the wordplay.
I cannot really understand how this works, but
'about' could be 'ca' (abbreviation for 'circa') and 'ca' is found within the answer.
'big' could be 'os' and 'os' is found in the answer.
'son' could be 's' (genealogical abbreviation for son) and 's' is found within the answer.
The remaining letters 'bert' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...

'in' acts as a link.

Can you help me to learn more?