In Boston powers are real heroes are rare and Jack McGriskin is a private detective with a strong right arm and a nose for troubleWhen a missing person he&39;s been hired to find turns up dead he stumbles into a network of corruption stretching from the streets of Boston to the halls of Congress and the clues lead him back to a world he&39;d left behind And just as things are starting to get back to normal a new shadow falls across his path in the form of the mysterious UsurperCollects Jack Hammer 1-4 and Jack Hammer Usurper 1-2