A conflicted irreplaceable right hand man to a mob boss, finds his warnings disregarded in a tug of war between two warring bosses for his allegiance. ? ??

oh I see it's not even a film you're working on. Why am I wasting my time then?

To clarify your grammar:

We don't put commas after the subject and before the verb.

The subject is the 'right-hand man' and 'finds' is the verb.

We wouldn't say 'The boy, kicked the ball.'

We'd say 'The boy kicked the ball.'

If anything 'to a mob boss' should be in brackets.

The sentence would read fine as:

"An irreplaceable right-hand man finds his warnings disregarded in a tug of war between two warring bosses..."

or

"An irreplaceable right-hand man (to a mob boss) finds his warnings disregarded in a tug of war between two warring bosses..."

Ok, well, you're unteachable. Become teachable.

Sorry Grammer teacher but your sentence - 'dude, I think you're out with your commas. You defo don't need one after boss' - doesn't make any sense.
Sorry but 'Millers Crossing' is actually a real film, the Logline is in the wrong spot.