Shadow of the Black Mamba

It's been two years since the destruction of both the Gangster Federation, and Lord Magnus, in Saints City. Daniel Stone, better known to the criminal underworld as the Black Mamba, still continues his amoral mercenary profession for both the British Government and independent clients.
The Black Mamba's main weapon is modified non-lethal snake neurotoxin, which not only paralyses his victims, but provokes repentance.
When the Black Mamba is recruited by MI6 to bring down a Colombian cocaine baron in the Peruvian Amazon, what starts as a simple mission soon becomes extremely complicated, and deadly.
The situation is convoluted further with the arrival of a mysterious doppelganger of the Black Mamba, who claims to have been wronged by him in the past, and is now on a determined hunt for revenge.
With so many various adversaries, the chances of survival are slim - even for someone as skilled as the Black Mamba.