Australia's first locally produced science-fiction television program and one of the earliest Australian television programs to be sold overseas, The Stranger followed the adventures of 'Adam Suisse', an alien visitor to Earth. G.K. Saunders had previously written the story as a BBC radio series.
Nan Musgrove's review summarises the plot of the first series as follows:
'"The Stranger," called Adam Suisse (Ron Haddrick), is a being from Soshuniss. He arrives on earth by spaceship, and during a terrific storm is found on the doorstep of the Sydney home of the headmaster of a boys' school.
'He is taken in by the family, and given a job at the school as a master.
'His relationship with the headmaster's son and daughter and one of their friends results in the three teenagers visiting Soshuniss–a visit that is a first-class international mystery.'
Source: Nan Musgrove, 'Kids!–You Can't Fool Them', Australian Women's Weekly, Wed. 29 April 1964, p.15.
The first series ended with the inhabitants of Soshuniss (which can no longer sustain its population) being offered sanctuary in Australia, after an agreement is reached between them, the Australian government, and the United Nations.
However, producer Storry Walton noted in another interview that the second series would complicate the political situation:
'Enormous complications will take place in Australia, New York, and on Soshuniss' [...]
'For instance, the people of Australia, who had accepted wholeheartedly the good intentions of the people of Soshuniss, begin to doubt them. On top of this, there is a revolution on Soshuniss and a new and militant leader is appointed who appears to be a threat to the whole world.'
Source: Nan Musgrove, 'U.S. May Buy A.B.C. Series', Australian Women's Weekly, Wed. 19 August 1964, p.19.
Both writer and designer went to great length to add complexity and depth to the alien aspects of the program. For example, script-writer G.K. Saunders devised an 'alien' language for the inhabitants of Soshuniss to speak among themselves, and ensured that they spoke English with a 'foreign' accent (hence the humans' assumption that The Stranger is Swiss). Similarly, the Soshunissian spaceship was carefully vetted by the CSIRO, to ensure that it was as plausible a spacecraft as possible.
Radio and television versions:
The relationship between the six-part radio series produced on the BBC and the ABC's television version is not entirely clear. The BBC radio version (also written by G.K. Saunders and with the same essential storyline as the series one of the television version) certainly preceded the ABC version, but it is unclear to what extent the latter is an adaptation of the former. It is also worth nothing that Australian newspapers, which promoted the ABC version widely, do not seem to have acknowledged the earlier BBC radio version.