Jewels of Aptor is a science fantasy novel by Samuel R. Delany that follows the tale of two adventuresome youths, Argo and Geo, as they make a perilous journey through the land of Aptor.  The novel is set in a distant future where humanity has spread across the stars and colonized many worlds.

Argo and Geo are hoping to find the legendary jewels said to be hidden in Aptor. These jewels are rumored to possess mystical powers, and their acquisition would bring immense wealth and power to their owner. As they begin their journey, they are attacked by a group of savage, mutated creatures called the Ghouls. Fortunately, they are saved by a group of warriors called the Pelicans, who take them in and nurse them back to health.

The two youths soon learn that the Pelicans are searching for a missing member of their tribe, a man named Venn. Venn had left on a quest to find the source of a mysterious energy that surrounds Aptor, and his search had taken him deep into the wilderness. The Pelicans were worried for his safety and had been searching for him ever since.

Argo and Geo, always in search of adventure, offer to accompany the Pelicans on their quest to find Venn. They journey through the harsh terrain of Aptor, braving dangerous creatures, treacherous mountains, and treacherous rivers. Along the way, they encounter a variety of strange beings, including a group of electrically charged, flying creatures known as the Scorp-Spiderwings.

Their journey leads them to a strange and powerful being named Gaylord, who possesses immense psychic powers. Gaylord explains to the group that Aptor is a nexus of power, a place where the energies of the universe converge. He reveals that he has sensed the presence of Venn, and that he is in great danger. He offers to guide the group to Venn's location, but warns them that they will have to face his nemesis, the dark sorceress Vazkor.

Vazkor is a powerful witch who has been corrupted by the power of Aptor. She has been searching for the jewels, hoping to use their power to control the universe. She has captured Venn and is holding him captive in her fortress.

The group engages in a fierce battle with Vazkor's minions, but are ultimately unable to penetrate her fortress. They retreat and regroup, and with the help of Gaylord and his powers, they are able to penetrate Vazkor's defenses. They storm the fortress and engage in a final, desperate battle with Vazkor and her minions.

In the end, the group is victorious, and they are able to free Venn from captivity. Vazkor is defeated, and her hold on Aptor is broken. The jewels are recovered, and the group departs Aptor and returns to the stars, with their lives forever changed by their experiences on the mystical planet.

Jewels of Aptor is a gripping tale of adventure and discovery, filled with unforgettable characters and fantastical landscapes. It is a classic of science fantasy, and a must-read for fans of the genre.