While traveling home from an escort mission, the crew of the USS Defiant receive a distress call from Captain Lisa Cusak, a Starfleet officer stranded on an alien world by herself, after her ship has been destroyed by actively scanning a strange planet. After working a means to communicate with her, they discover that she is stranded on a Class-L world with a high concentration of carbon dioxide in the atmosphere that will eventually kill her without regular doses of "triox" medication, which she is running out of. Dr. Bashir tells her to cut her dose such that she will survive the six days that it will take the Defiant to reach the planet. In turn, Captain Cusak asks that they keep a constant conversation going with her to keep her alert and to make her feel less isolated.
As they travel, each of the crew becomes somewhat closer to Captain Cusak as they explain their own personal problems with her. When Dr. Bashir discovers that Cusak's supply of triox is more critical than they thought, Captain Sisko orders the phaser bank power to be routed to structural stability controls to increase the Defiant's speed. They arrive at the planet shortly after Cusak has fallen unconscious, giving them a limited amount of time to find her. After figuring out how to bypass a strange energy field that surrounds the planet with a shuttlecraft, the crew finds the long-decomposed remains of Cusak's body deep in a cave, having been dead for about three years. O'Brien theorizes that the energy field caused their communications to travel through time. Sisko orders them to collect Cusak's body and gives her a proper burial back on Deep Space Nine as a Starfleet officer and trusted friend.
Meanwhile, Quark talks Odo into preparing an extravagant celebration of his one-month anniversary with Major Kira. He tells Jake, who is writing a story about criminals, that while Odo is occupied he will sell rare crystals for profit. However, Odo decides to change his romantic evening for the following night, ruining Quark's plan. Taking pity on him, Odo decides to let him off this one time and has his evening with Kira when he originally planned.