This tale of international intrigue is set in motion by the death of Chuck's old war buddy Terry (played by Norman Alden in a brief role), who were combat photographers during WW II. He has left for Chuck negatives implicating an industrial espionage crime ring headquartered in Lisbon, where our hero visits to get to the bottom of the matter.
Authorities there are confident that Terry was in fact working for the criminals rather than trying to expose them, and now Chuck has to clear his friend's name, with the help of Terry's widow Chana Eden (a TV actress whose career highlight was her femme lead role debut in the feature "Wind Across the Everglades").
A very fine performance here is delivered by Mario Alcalde, as the smoothie villain who manages to fool Chuck for most of the show, until our hero discovers Terry's hidden camera and the negatives which implicate Mario and clear Terry.
As always, Chuck's earnest performance carries the show, with very little to no local atmosphere developed (a brief nightclub scene) to indicate we're in Lisbon.