They killed the wrong man's family.

Retired SWAT Captain Jeff Geronimo thought his days of violence were over. Living quietly in his best friend's backyard, he's content to drink coffee and watch the world go by—until he witnesses his elderly neighbor being beaten by drug dealers on his own street.

What starts as a simple good deed spirals into a deadly game of cat and mouse when Jeff discovers the "harmless retiree" next door is actually a seasoned drug dealer who's stolen fifty thousand dollars from a Mexican cartel. Now the cartel wants their money back, and they don't care how many innocent families get hurt in the process.

But El Martillo and his crew made one critical mistake: they threatened the wrong neighborhood. Because Jeff Geronimo isn't just a retired cop with anger management issues—he's the heir to five centuries of ninja tradition, and his family has been solving problems permanently since before America was a nation.

Some men are dangerous. Others are deadly.

Jeff Geronimo is both.

From the author of the ninja The Outfit series comes a new kind of hero—part Robert Parker's Spenser, part deadly shadow warrior. Fast-paced, gritty, and filled with authentic martial arts action, GERONIMO introduces readers to a protagonist who proves that the best defense is often a very creative offense.