British tennis player Peter clutches to an embarrassingly low position on the tennis-ranking ladder. Handed a wild card for Wimbledon, he expects it to be his final bow.
A race of giant Gastropods has taken over the planet Jaconda. Their leader, Mestor, now intends to cause an enormous explosion in order to spread his people's eggs throughout the galaxy, and he kidnaps juvenile twin geniuses from Earth to work out the necessary mathematical equations. Space fighters led by Lieutenant Hugo Lang are dispatched to get the twins back, but they come under attack and Lang is the sole survivor when his ship crashes on the asteroid Titan III. A newly regenerated Doctor and Peri become involved and help Jaconda's elderly former ruler Professor Edgeworth, who is really a Time Lord named Azmael, to defeat Mestor and free the planet's bird-like indigenous people from the gastropods' reign of terror. Azmael, however, sacrifices his life in the process.
Nora Helmer has years earlier committed a forgery in order to save the life of her authoritarian husband Torvald. Now she is being blackmailed, and lives in fear of her husband finding out, and of the shame such a revelation would bring to his career. But, when the truth comes out, Nora is shocked to learn where she really stands in her husband's esteem.
