Wythnos yng Nghymru Fydd

[1] Set in the 1950s, the narrator Ifan Powel takes part in a time travel experiment and lands in Cardiff in the year 2033.

He finds that Wales has secured self-government and is prosperous economically, and socially harmonious; everyone is bilingual in both Welsh and English.

This converts Ifan into a Welsh nationalist (he had previously been opposed to nationalism) and he swears to do everything within his power to ensure that the Wales that he visited first is the one that will be realised.

The novel is significant in the history of Welsh-language literature in that it was the first major science fiction work for adults to be written in the Welsh language[citation needed], but it has been argued[by whom?]

that the fact that it is (on the author's own admission) a blatant work of political propaganda diminishes its literary value to an extent.