1917. On a battlefield near the River Escaut, John lies in the aftermath of a blast, unable to move or feel his legs. Struggling to focus his thoughts, he is lost to memory as the snow falls—a chance encounter in a pub by a railway, a hot bath with his lover on a winter night.

1920. John has returned from war to North Yorkshire, near a different river. He is alive but still not whole. Reunited with Helena, an artist, he reopens his photography business and tries to keep on living. But the past erupts insistently into the present, as ghosts begin to surface in his pictures: ghosts with messages he cannot understand.

So begins a narrative that spans four generations of connections and consequences that ignite and reignite as the century unfolds. In radiant moments of desire, comprehension, longing, and transcendence, the sparks fly upward, working their transformations decades later.