With the conflict between the Klingons and Cardassians taking its toll, a shipment of desperately- needed replicators destined for Cardassia is set to pass through Deep Space Nine. Odo and Lt. Commander Eddington of Starfleet Security recommend heightened measures to deter both the Klingons and the terrorist group known as the Maquis, then reveal some troubling news -- they believe there is a Maquis smuggler aboard the station, and they have some evidence that the smuggler is Kassidy Yates, Sisko's romantic interest. After hearing the basis for their suspicions, Sisko must order them to investigate the woman he cares for.