The action pics up with Cap protecting a villain in witness protection called the porcupine from a gunman.
Flashback to a week ago, and a regular sort of looking guy who happens to be armed with tech he plans to use for petty reasons is killed by the new Scourge.
The police find an AIM suit in his apartment, and just then, Dum-Dum Dugan and Rachel Leighton arrive to take over the investigation.
It turns out that all the Scorge's victims are recent entrants into the witness protection program.
Dum-Dum and Diamondback reminisce a bit about her past with Steve, and she says that one way or another, she's always trying to impress him, such as she does by holing up with one of the suspected targets, the viper.
Steve tracks down the source of the leak to three people in his employ, and before he can do the parlor scene, one of them pulls a gun, opens fire, and jumps out a window shouting "Hail Hydra". He has a flying rig, but Cap still take him out.
The mole makes does the standard gloating before dying of a cyanide pill.
Despite Diamondback's efforts, the Scourge gets to viper and wounds Rachel, though he doesn't kill her. At least not yet. She apparently recognizes his voice.
My verdict: Brubaker is back in form. Arm and story are top notch.