Sin City screeches to a halt as a massive power outage brings down the light of the strip, locking down the Montecito, while a mysterious hotel guest is shot on the casino floor. In the midst of the blackout, super sleuths Nessa and Delinda attempt to find the casino killer, while a semi-delirious Sam flirts with paranoia as she suspects the murder to be part of an elaborate cover-up. Elsewhere, a trapped Danny and Mary spend the blackout rehashing some old feelings, while a claustrophobic Mike works tirelessly to free Ed and himself from the lockdown surveillance room.

An action star dies while executing a stunt for his latest movie; a rival casino host squares off against Sam for the patronage of a high roller.