Newly promoted Captain Hensley is on route to Narendra Station to assume command of the USS Faleiro NCC-7100. He is accompanied by two members of his crew: Chief of Security Tahna Laren and Chief Medical Officer Shon th'Eneher. They are enjoying the comforts of the USS Odyssey, a Galaxy-class starship under the command of Captain Keogh, when a Priority One communiqué from Starfleet Command diverts the Odyssey from her assigned route. Keogh orders all stop and provides Captain Hensley and his crew with a Danube-class runabout. Launching from the main shuttlebay, Captain Hensley signals the USS Odyssey. The two captains wish one another smooth sailing and just as the com-link ends, Hensley and his crew hear Keogh give the order to leave at maximum warp.
Alone on the frontier of Federation space in the Beta Quadrant, the three officers continue on to Narendra Station. Each officer expresses their concern about the Priority One message and what it might mean for the Federation and Starfleet. Have the Borg returned? Starfleet couldn't afford another Battle of Wolf 359. Was it the Romulans, the Cardassians, the terrorist Maquis, or some new threat? Hensley thinks of his time as First Officer aboard the USS Gallant, destroyed by Maquis sabotage near the Demilitarized Zone and wonders if Starfleet can ever truly return to its heyday of peaceful exploration.
During the trip, they receive a distress call from a science outpost on a planet that’s been struck by a highly irradiated ion storm. The runabout crash-lands on the surface, and the crew is attacked by primitive hostile humanoid creatures wielding clubs and rocks. After dealing with the primitives, the crew make the journey from the crash site to the science outpost, overcoming various obstacles along the way. At the science outpost, the crew learns that they have all been exposed to the same environmental effects that caused the members of the members of the science outpost to to devolve into Neanderthals.
Rescuing Doctor Schipp and her assistant Doctor Jasper Conrad from a locked compartment, Shon th'Enehr assists them in devising a treatment to reverse the affects of the devolution while Captain Hensley and Lieutenant Tahna find the parts needed to repair the runabout. Inoculating the scientists and themselves and with little time to spare before the full brunt of the ion storm destroys all life, they complete the outpost's mission by gathering the flora needed to treat Irumodic Syndrome, a terrible disease ravaging several Federation colonies.
Unable to locate four remaining devolved scientists, the crew have no choice but to save who they can before it's too late. Tectonic tremors brought on by the powerful ion storm would soon tear the planet apart. In a race against time, they repair the runabout, escape the planet and set course for Narendra Station.