After the murder of Illinois Detective Agency founder Charles Porter by a mysterious criminal named King Valdez, the team comes together to Valdez and bring him to justice.

King Valdez is kidnapping children and selling them into slavery around the world. James Duffy assumes control of the agency and works closely with the Justice Department to find Valdez, who uses hired privateer ships to smuggle kidnapped children out of the country. A manhunt leads to the capture of several privateer captains, who, in exchange for lenient sentences, give up Valdez. Valdez is hiding in the Sonoran Desert.

After an intense battle, Valdez is captured and returned to the Justice Department in Washington.