In the vibrant backdrop of 1880s London, a gripping tale of political intrigue and impending disaster unfolds. Eifion Price, an impassioned Welsh nationalist, works as a guard on the Irish Mail train, simmering with a desire to make the oppressors of his beloved country suffer. Little does he know that Edward Mulholland, a member of the Irish Republican Brotherhood, sees in Eifion the ideal instrument to exact revenge on England.

Meanwhile, Thomas Wells, a seasoned and uncompromising detective from Scotland Yard, receives a directive from his superiors: investigate a troubling rumour of an impending attack in London, orchestrated by the I.R.B and involving a Welsh accomplice. Unbeknownst to him, a carefully concealed bomb has been smuggled into the country from Ireland, its deadly detonation poised to claim countless lives. As Thomas delves deeper into the investigation, he unwittingly attracts the chilling attention of the I.R.B, transforming him into their next target.

With each passing moment, the day of unfathomable horror creeps closer, and time becomes an unrelenting adversary. Will Eifion succumb to Mulholland’s machinations, or will his conscience steer him away from the path of destruction? Can Thomas decipher the puzzle before innocent lives are irrevocably shattered? As the clock ticks relentlessly, the tension mounts, propelling readers on a suspenseful journey through a world on the brink.