Settling up the score

Puffer:
Here to track this man in black am I
With one clue as to the who and why!

Datchery:
I find myself
In this aggravating form and face
Gravitating to this place
Navigating t'wards this case!

Puffer & Datchery:
I've come to town, my ear at every door
Half the clown, yet crafty at the core
Settling down to settle up the score
A kettle full of fish I'll fry
I'll cook each goose, (to mix a metaphor)
and unloose a mighty meteor
I'm settling down to settle up the score

Datchery:
My mettle will be more than tested!

Datchery & Puffer:
A debt'll be repaid before I've rested - oh!

Datchery:
Drood

Puffer:
No word

Datchery:
What's brewed

Puffer:
No grave

Datchery:
No tomb

Datchery & Puffer:
Who'll say who's done what and why to whom?

Datchery:
I'm on the scent, I'm inventing everything I am

Puffer:
Where's the sacrificial lamb?

Datchery:
'Ere in bloody Cloisterham

Puffer & Datchery:
I've come to town to ask at every door
Did Edwin Drood drown or was he washed ashore?
I'm settling down to settle up the score:
Red herring on a briny beach!

I'll solve this yet
As Grand Inquisitor!
Make a bet
You've met me once before!
Make a threat?
I only wish you would!
I'm settling up the score for good!