Plot listening comes way before external editing or beta reading. It comes around draft 4 for me, but it depends how you count and everybody’s different. PLs don’t even need to read the draft, they just have to be patient enough to listen as you mangle and chunter your way haphazardly through the ill-formed ragbag of half-formed ideas and rough-hewn, lumpy characters that is the early draft of a book. You can be repetitive and vague, over-specific, longwinded and forgetful about names (Did I say Aberdeen? I meant Nairobi.) yet somehow this patient person sits through it.
With crime writing it seems especially important because the twists and clues and red herrings the genre must have are too much for the ordinary (at least the fairly sane ordinary) human brain to contain all at once. It’s only when you run it past a listener that the awful omission of X or the impossible condition of Y suddenly becomes clear.
The PL sits up and asks something like, ‘But isn’t B in Moscow?/Where did you say he left the grenade?/Shouldn’t A have left with V after Fritz found the envelope, not before?’ and they’re right, and you, the shambolic writer, until then bitter and apathetic, are electrified by this helpful observation and leave your coffee to grow cold on the table, so swiftly do you sprint off in the direct of the laptop.
Hurrah for the patient plot listener! Find one immediately if you can. And reward them well. Jam is good for this, or pizza, but beer and sex* are fine too.
If they write things too, you probably owe them some PL time in return. But sex is obviously quicker*.
*only in certain circumstances, obviously