Shimada, a former Self-Defense Force member, suffers from severe PTSD following the loss of a comrade in a firefight in war-torn South Sudan, a tragedy covered up by the government. Shining a light into Shimada's solitary life in illegal arms manufacturing is a job as an apprentice at a traditional Japanese fireworks factory. There he begins crafting fireworks alongside the master artisan and fellow craftsmen who embrace fireworks that illuminate people's peaceful lives. Yet, parallel to Shimada's journey, his comrades-in-arms with unresolved feelings team up on radical acts to expose the government's cover-up, escalating tensions and pulling Shimada back into the darkness he thought he'd left behind.