| Christopher |
Amato | Pete's brother |
| Jenn |
Amato | Pete's wife |
| Pete |
Amato | Construction worker and victim |
| Crispus |
Attucks | First person killed during the Boston Massacre |
| Ashley |
Barrett | Holt's teaching assistant |
| Mark |
Boyle | Member of "The Founders" |
| Harris |
Briggs | Boston detective |
| Charlie |
Crain | Journalist |
| Lillian |
Dale | Parker's house manager |
| Vince |
Darcy | Charlie's boss |
| Sharon |
Esposito | New supervisor in charge of the forensic unit |
| Frank |
Flynn | Justin's attorney |
| Benjamin |
Franklin | Historical figure referenced as ancestor of Charlie |
| Parker |
Gage | Founder of "The Founders" and relative of Thomas Gage |
| Thomas |
Gage | Commander-in-chief of British forces and governor of Massachusetts Bay |
| George |
Germain | Secretary of State for the American Colonies |
| Oliver |
Graham | Medical examiner |
| Nathan |
Hammond | Victim |
| John |
Hancock | Signer of the Declaration of Independence referenced |
| Albert |
Hill | Man in possession of Thomas Gage's dagger |
| Anthony |
Holt | American history professor at Harvard |
| Declan |
James | Kate's oldest friend and FBI partner |
| Walter |
Kelly | News10 broadcaster and former member of "The Founders" |
| Margaret |
Kemble | Wife of Thomas Gage |
| Carmen |
Langston | District attorney |
| Justin |
Lewis | Holt's former teaching assistant |
| Ken |
Miller | Chief of security |
| Robert Treat |
Paine | Signer of the Declaration of Independence |
| William |
Prescott | Revolutionary War colonel referenced |
| Paul |
Revere | American patriot and silversmith referenced in historical context |
| Ebenezer |
Richardson | British informer |
| Christopher |
Snider | Boy killed by Ebenezer Richardson |
| Martin |
Spade | Kate and Declan's FBI handler and supervisor |
| Joe |
Walsh | Kate's grandfather and Harvard professor |
| Joseph |
Walsh | Ambassador, Kate's father |
| Kate |
Walsh | Protagonist. Aka: Katie |
| Madeline |
Walsh | Kate's mother |
| Joseph |
Warren | American physician and Revolutionary leader referenced |
| Amy |
Wheeler | Researcher |
| Jordan |
Williams | Victim |
| Simone |
Williams | Jordan's widow |
| Bryanna |
| Justin's girlfriend |
| Larry |
| Kate's neighbor |
| Lauren |
| Declan's ex-wife |
| Mary |
| Kate's next-door neighbor |
| Maryanne |
| Witness |
