1918. Boston. A city in turmoil as soldiers return home from World War One, bringing with them an epidemic of Spanish influenza.

Danny Coughlin is the son of one of Boston's most powerful police captains. An undercover cop, he is hunting for revolutionaries and anarchists who, in the aftermath of war, are pledged to overthrow the city's ruling classes. But Danny soon finds his ideals compromised as, drawn into the conflict, his family starts to question where his loyalties really lie.

Luther Lawrence is on the run. Having survived a murderous confrontation with a crime boss, he lands a job in the Coughlin household. But it isn't long before his dangerous past and his tenuous present are on a life-threatening collision course.

As the city goes into meltdown, Danny and Luther must confront the storm of violence that threatens to engulf them if each is to survive...