When 27 people are killed at a diplomatic conference on Earth, and the Changelings are the chief suspects, Odo and Captain Sisko travel to Earth to investigate what looks like a bold new offensive by the Dominion that could lead to war. Joining forces with Vice-Admiral Leyton, they begin to introduce new security measures, hoping to be prepared if the Changelings attack again. With the Dominion threat ever looming, paranoia begins to grow, and even Sisko momentarily suspects his own father of being a Changeling. As matters escalate, all the power on Earth is knocked out, and sabotage is believed to be the cause. Sisko and Leyton decide to prepare Earth for war, and they convince the President to declare a state of emergency on Earth.

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