Olwen Pendennis and her Guardian live in splendid isolation on the planet Isis of the star Ra, maintaining the beacon which announces the presence of this habitable planet to any space travelers, till the day of Olwen's tenth birthday. She would be sixteen in earth years, and she has never seen anyone but Guardian.

But eighty settlers arrive in the space ship Pegasus Two, with Captain Jonas Tryon. They will now live on the planet that Olwen has considered her own. She tries to put aside her childish, selfish impulses and finds herself curious about the newcomers. Guardian makes her an isolation suit with a face-mask, to protect her in case the settlers have any germs which would harm her.

Mark London is one of the settlers. At seventeen, he is the oldest of the twenty children among the settlers, and Jody N'Komo is the youngest at nine. Mark is curious about the high places above their valley, which the settlers cannot explore without an oxygen breathing mask and an ultraviolet-opaque suit. Among the young settlers, he is the only one who takes Olwen's invitation to visit her home, and the mesa and the trail to the northern mountains when the settlers have acclimatized. They become friends almost at once, talking of her shy pet animal Hobbit.

The day after they meet, Mark climbs as high as Olwen's home, half-way up the cliff, but can go no higher. Two days later, Mark asks the doctor Phil MacDonald to take a sample of Olwen's blood to see if she is at any risk from germs from the settlers. Then Mark and Olwen climb together to the top of her mesa, and he understands the beauty of the high places.

Olwen resents how her suit and mask keep Mark from seeing and knowing her, as she has come to love him. She tells Guardian that the doctor took her blood sample and will soon be able to prove that the suit is unneeded. Guardian confronts the doctor, demanding that the blood sample be returned. Mark hears them argue as the doctor demands to know what Guardian is hiding. Sent away, he takes an oxygen mask and UVO suit and climbs the cliff. Mark finds Olwen is not at home but on the mesa. When she hears Mark call, she turns. Mark staggers to his feet and steps backward. In horror, he falls and she watches him drop.

Olwen climbs down to where Mark is caught on a spur of rock and puts his oxygen mask against his face again. When Guardian leaves the settlers' village far below, Olwen tosses a rock which alerts him so he spies her. Guardian climbs up quickly and sends her to radio the village, then get a floater car ready so he can take Mark to the doctor.

Guardian returns to tell Olwen that Mark will recover, but it is not advisable to visit him. He does not love her yet as she loves him because he does not know her properly.

Olwen is deeply distressed and goes to walk in the valley. Her pet Hobbit comes to play with her, a large animal that she has left alone since the...

(The entire section is 1201 words.)