Dexter is back, struggling between his love for killing and his job in the homicide department. Although committed to carrying out his twisted brand of vigilante justice, Dexter begins to doubt his murderous capabilities and continues to be haunted by his tortured past. His difficulties multiply when evidence of his deadly after-hours activities begin to surface and the FBI is brought in to investigate the city's new serial killer dubbed the "Bay Harbor Butcher." Dexter can't pause for a breath as the noose tightens and the questions keep mounting. Will he be able to continue his serial-killing ways? Or will Dexter's dark past finally be uncovered?