A Thracian warrior is captured and enslaved by Romans, then placed in gladiator school, where he battles to save his life, gain his freedom and become reunited with his wife, who was also condemned to slavery.
As the leader of the newly freed slaves, Spartacus begins to understand the importance and overwhelming responsibilities of his task. Meanwhile, Claudius Glaber arrives in Capua, compounding Spartacus' problems.
After Spartacus' men liberate a Roman villa, the newly freed slaves are wary and unsure of their new situation. Meanwhile, Oenomaus throws himself into the Pits, and Glaber believes Lucretia's prophecies, although Ilithyia isn't convinced.
After learning of Naevia's fate, Spartacus must deal with a rift among the gladiators; Lucretia divulges a long-kept secret in order to strengthen her position; and the rebels find themselves at risk after an attack.
While Spartacus attempts to lead survivors through the woods to safety, Crixus becomes separated from the group and finds himself at a place that dredges up painful memories. Elsewhere, Lucretia digs into Ilithyia's past to seek favor with a high-ranking Roman.
Spartacus and the rebels look to increase the size of their force by freeing and recruiting fighters held as slaves during foreign wars; Lucretia recruits one of her husband's ex-gladiators in an attempt to outmaneuver influential Romans.