Row about engagement, one thing leading to another (5,8)
I believe the answer is:
chain reaction
'row' is the definition.
(thesaurus)
'about engagement one thing leading to another' is the wordplay.
I cannot quite understand how this works, but
'about' could be 'inre' (I've seen this in another clue) and 'inre' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'to' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for chain reaction that I've seen before include "inevitably following flush?" , "Series of events each caused by the previous one" , "Series of linked events" , "that could get out of control" , "Self-maintaining process" .)