A piece of land is what it’s all about (4)
I believe the answer is:
plot
'a piece of land' is the definition.
(I know that plot is a type of area of land)
'what it's all about' is the wordplay.
I cannot quite understand how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
The remaining letters 'plo' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'is' acts as a link.
Can you help me to learn more?
(Other definitions for plot that I've seen before include "Secret plan; graph" , "Vegetable garden - scheme" , "garden area" , "Gunpowder, for one" , "Conspiracy, secret plan" .)