Set in London during World War II, "The Heat of the Day" is a story about a love triangle between Stella Rodney, her lover Robert Kelway, and Harrison, a man who claims to be an intelligence agent. Harrison informs Stella that Robert is selling secrets to the enemy, and in exchange for his silence, he wants Stella all to himself. The novel explores themes of trust, deceit, and the complexities of love against the backdrop of a city under siege.

This espionage novel follows the life of Magnus Pym, a high-ranking British intelligence officer who disappears after attending his father's funeral, causing a massive manhunt. As the intelligence service scrambles to find him, the narrative dives into Pym's past, revealing his complex relationship with his conman father and his recruitment into the world of espionage. The story is a complex exploration of betrayal, identity, and the blurry line between loyalty and deception.

The novel explores the life of a Spanish expatriate in England who is recruited by a secretive organization due to his unique ability to interpret people's behavior. As he becomes entangled in a world of espionage, he grapples with moral and ethical dilemmas, questioning the validity of his work and the consequences of his actions. Through a blend of introspective musings and suspenseful narrative, the protagonist's life unravels, revealing a complex web of deceit, betrayal, and violence.