In September of the year 2385, the Argus was assigned to patrol the Federation-Tzenkethi Coalition border in the Helaspont sector. It provided twice daily status updates to Helaspont Station on the far side of the sector.
After detecting an unknown vessel crossing the border towards Tzenkethi space, the Argus pursued it into unclaimed space in the Helaspont Nebula. Emerging from the nebula, the Argus found itself surrounded by three Tzenkethi harriers under the command of Nenzet Siv Vel-C. It re-entered the nebula to evade the Tzenkethi ships, managing to avoid the weapons fire directed into the nebula. It was rescued by the USS Robinson when Captain Benjamin Sisko intervened with the Tzenkethi, then escorted the Argus back into Federation space. (DS9 novel: Sacraments of Fire)