Spots 
Teddy Wright trades a spoiled Adirondack vacation for a month aboard the steam yacht Sea Dream with his friend Neal Emery. What begins as a gentle coastal voyage from Bridgeport south toward Nassau quickly loses its easy novelty as oppressive tropical heat takes over. Near the Providence Channel, an ominous stench and rising heat signal that an unseen disaster has already taken hold below deck.
INTRODUCTION. → CHAPTER V.
Fire guts the Sea Dream before the crew can extinguish the flames, forcing all hands into tiny open tenders. Engineer Jake Foster steers one small boat through a dark night storm, separating Neal and Teddy from Neal's father in the heavy swell. Driven westward by strong winds, the survivors crash against the jagged coral reefs of Yucatan. The ruined boat leaves the castaways stranded on an unknown shore.
CHAPTER VI. → CHAPTER XI.
Guided by the mysterious explorer Cummings and the native scout Poyor, the castaways penetrate deep, venomous swamps. Clambering up a giant cypress, Neal and Teddy behold the Silver City, its alabaster walls and burnished dome gleaming brilliantly against surrounding cliffs. The team slips into the forbidden metropolis under cover of night. They take shelter in an abandoned outer building, surrounded by hostile Chan Santa Cruz inhabitants.
CHAPTER XII. → CHAPTER XVII.
Trapped in enemy lands, the party retreats to subterranean caves where Poyor treats wounds with crushed guaco leaves and roasts clay-baked tohs. Hostile sentinels patrol the jungle paths, threatening the fugitives with deadly nahuyaca poison arrows. Moving only under cover of darkness, the group shifts from cave to cave to evade relentless search parties. Survival depends on total silence and absolute obedience to their native guide.
CHAPTER XVIII. → CHAPTER XXIII.
After Jake wanders off and nearly exposes their location, Neal and Teddy refuse to abandon the reckless engineer despite Cummings' anger. Reunited, the fugitives begin a grueling ascent up sterile, sun-baked mountain ledges with rapidly dwindling water rations. A violent tropical rainstorm suddenly bursts over the range, drenching the travelers. They take precarious shelter under an overhanging cliff face while torrential floods sweep the ravines below.
CHAPTER XXIV. → CHAPTER XXVII.
A sudden landslide obliterates the trailing enemy force beneath the cliff, opening a clear path to the summit where the Caribbean Sea finally comes into view. Descending toward the coast, the group feasts on roasted armadillo while witnessing a violent jungle battle between a giant boa constrictor and two jaguars. Safe on the shore, Teddy and Neal prepare for their voyage home, having survived the perils of Yucatan.
CHAPTER XXVIII. → CHAPTER XXXIII.
An ill-fated yachting trip turns into a perilous trek across Yucatan in search of a legendary hidden Mayan city.