A young slave living in the Kansas territory in 1856, has a fateful run-in with abolitionist John Brown, who "frees" him, nicknames him "Onion" and welcomes him into his ragtag army. Series premiere.

Onion and fellow slave Bob cross paths with pro-slavery "red shirts" escorting them to the slave-trading town of Pikesville, MO. Onion finds himself enmeshed in a mounting slave insurrection where he learns the consequences of his...

John Brown travels north with Onion, taking refuge at the home of Frederick Douglass and his two wives. When Brown and Douglass clash over methodology, Onion discovers just how complex the fight for justice and human equality real...

John and Onion continue their fundraising mission, heading to Canada on foot. When Harriet Tubman endorses Brown in a room full of new recruits, Onion realizes that he may be more invested in the cause and the "old man" than he th...

Onion and new recruit John Cook head to Harper's Ferry to prepare for the arrival of John Brown and his army. Onion struggles recruiting African-American soldiers. Brown's arrival with daughter Annie creates a new distraction: tru...

The plan to take control of Harper's Ferry is finally put into action; however, a crucial mistake threatens the success of the entire operation. With shots firing, Onion is sent out to get reinforcements.

John Brown and his remaining army take a last stand as more federal troops descend upon Harper's Ferry. With John Brown captured, Onion, truly on his own, risks his life to say his goodbyes to Brown. Series finale.