Signet Unstoppable

The most vicious and amoral drug dealer on Earth has just been found guilty of his crimes and legally executed. But he won't stay dead... Is he now Unstoppable? He's just the first to return from beyond the undiscovered country. Is it a good thing to have the dead returned? Or is this plague of resurrections Unstoppable? There's an alien killer loose on Earth. He'll do anything at all to reach his target, and kill anyone in his way. He's impervious to bullets, grenades and anything else in the arsenal. Is he Unstoppable? Earth's only hope is the understaffed, under-armed and under-appreciated team at SIGNET. But can they prevent all the death - and life! - and misery currently facing the human race? Could it possibly be that they are Unstoppable?