Two guys start a risky new business to pay off a debt.

Molly McKay is a profoundly autistic twenty-something woman who has lived in an institution from a young age following her parents' death in a car accident. When the institution must close due to budget cuts, Molly is left in the care of her neurotypical, older brother, Buck McKay, an advertising executive and perennial bachelor. Buck forces her to undergo an experimental medical treatment, with unexpectedly drastic results.

Season two's storyline picks up right where season one left off: with the 44 B.C. assassination of Gaius Julius Caesar and the near-simultaneous death of Niobe, wife of Caesar's faithful bodyguard Lucius Vorenus. Diverted from his post after learning that Lucius, his assumed grandson, was in fact Niobe's illegitimate son, Vorenus now descends into near-madness over his failure to protect Caesar, his role in his spouse's death, and the rumored murder of his estranged daughters.