An underpaid banker gets a venomous dose of indigenous sorcery when he abuses a loophole to syphon money from a deceased account intended for a community group.

What's his goal? What must he do when he gets the venomous does of black magic?

An underpaid banker gets a venomous dose of black magic when he syphons funds intended for an indigenous community group.

That logline makes more sense,

saying "indigenous community group" works better than "indigenous sorcery."