In London near the end of World War II, 14-year-old Nathaniel and his sister Rachel are left in the care of an enigmatic figure named The Moth, their parents having moved to Singapore.

[1][2] The Moth affiliates with a motley group of eccentric, mysterious, and in some ways nefarious characters who dominate the children's experience early in the postwar period.

Nathaniel and Rachel are supposed to be boarders at their school when their parents leave, but after complaining to The Moth they are allowed to live at their home which is now populated by an odd mix of characters.

One of these is The Moth's friend, The Darter, who imports greyhounds into England for the purpose of illegal gambling and ferries explosives by barge from Waltham Abbey Royal Gunpowder Mills into central London.

Despite entertaining a fantasy that he will one day run into his daughter, Nathaniel continues to live his mostly solitary life leaving Agnes and her family undisturbed.

[2] As the title's term 'warlight' is thought to refer, literally, to the blackouts of World War II, Lively wrote that the novel's narrative is likewise "devious and opaque" and proceeds "by way of hints and revelations", that its characters are elusive and evasive, and that the novel has an "intricate and clever construction" requiring a close reading.

[2] As background, Alex Preston wrote in The Guardian that much of Ondaatje's literary career has been driven by the perception that "memory is the construct of the older self looking back".

[3] Calling Ondaatje "a memory artist", Preston wrote that the author "summons images with an acuity that makes the reader experience them with the force of something familiar, intimate and truthful".

[6] On August 19, 2018, former U.S. President Barack Obama included Warlight in his summer reading list, describing the novel as "a meditation on the lingering effects of war on family".

[10] Anthony Domestico wrote in The Boston Globe that "Ondaatje's is an aesthetic of the fragment", his novels "constructed, with intricate beauty, from images and scenes that don't so much flow together as cling together in vibrating, tensile fashion.