This is a good follow-up to the earlier story that introduced Oliver as a companion travelling with Steven and the First Doctor (Perpetual Bond). Here, Oliver, Steven and the Doctor arrive in the Tardis onboard a satellite orbiting Earth very far in the future, scavenging from what remains of the Earth Empire. This part of the story leads into what really becomes the main point of the story: a struggle for life against the inexorable laws of physics, when the satellite is destroyed by those same laws. Will Steven and Oliver live? And what is Oliver's secret that he carried with him from 1960's Earth? And what does the future hold for the three travellers? Because by the end of this story, we know that there is more in store for them all.
Peter Purves does a great job again as his character Steven, and as the First Doctor - he gets the querulous but caring tone just right for William Hartnell's characterisation. Oliver is a great companion, and I hope he is here for a few more stories yet before we catch up to the continuity of the classic series in The Massacre. While I admit to getting a bit lost in some of the explanations that Steven gives around the mathematics and laws of physics in this story, I think a second listen to the story will set that to rights; and my mathematic failings do not detract from either understanding the story, nor the full enjoyment of it.
Bring on more Steven and Oliver with the Doctor I say!