A party of American schoolboys traveling with their professor tours islands across the Caribbean—visiting Jamaica, Cuba, Hayti, Porto Rico, Martinique, and St. Vincent—mixing sightseeing with practical information about local life and geology. When news arrives that relatives are near volcanic centers, the journey shifts into urgent rescue and close observation of volcanic activity: at-sea encounters with eruptions, hazardous land excursions among vents, collisions and other perils, and intensive searches for the missing. Episodes alternate youthful pranks and sports with sober accounts of earthquakes and eruptions, ending in dangerous exploration and eventual reunion.