After a short scene-setting introduction, the novel is the book written by the protagonist, radio reporter Mike Watson, chronicling the events that took place when creatures from the depths of the ocean attacked humanity.

Mike and his wife Phyllis work for the (fictional) English Broadcasting Company (EBC) so are privy to decisions by government and scientific authorities, who alternatively try to counter the aliens' moves or stifle news to prevent panic.

The novel describes the course of an attack on humanity by creatures from the ocean depths, as told through the eyes of two characters: Mike Watson, a journalist for the English Broadcasting Company (EBC) with his wife and colleague Phyllis; and Professor Alastair Bocker, who is more clear-minded and far-sighted about the developing crisis than everybody else but who often alienates people by telling brutally unvarnished and unwanted truths.

Mike and Phyllis are witness to several events of the invasion, which proceeds in drawn-out phases; it takes years before the bulk of humanity even realises that the world has been invaded.

"[5] New York Times reviewer J. Francis McComas similarly noted that while the novel was "somewhat quieter in tone" than Triffids, it would "nevertheless exert an even more lasting effect on the imagination.

A 1965 radio adaption by Eric Cameron was recorded in Vancouver by the Canadian Broadcasting Corporation, starring Sam Paine, Shirley Broderick, Michael Irwin and Derek Walston.

[8] BBC Radio 7 presented an unabridged reading by Stephen Moore of the novel in sixteen 30-minute episodes, produced by Susan Carson, and broadcast daily between 12 March and 2 April 2004.

On 28 May 2016 Radio 4 broadcast an adaptation by Val McDermid set in the present day, with some of the action moved from Harrogate to Birmingham and from Cornwall to Scotland.

It starred Paul Higgins as Michael and Tamsin Greig as Phyllis and featured an appearance by Scotland's then First Minister Nicola Sturgeon as herself and was recorded with live accompaniment by the BBC Philharmonic orchestra.

[9] [10] [11] [12] The new elements the script incorporates include an upgrade to Wyndham's predicted 100-foot rise in sea level to the worst-case figure of 70 metres envisioned over a thousand-year period by climate change experts.

[13] In 2017, Charisma Entertainment signed an agreement with John Wyndham's estate for the exclusive rights to develop an immersive, interactive game version of the novel.