Janeway's attempts to beam up 20th-century computer mogul Henry Starling and the timeship in his possession are stymied because Voyager's long-range transporters aren't working. As a result, brilliant astronomer Rain Robinson lures Starling to a meeting where the crew hopes to hijack him. Starling shows up with the Doctor, whom he's supplied with a 29th-century portable holo-emitter that allows him to exist in environments without standard holographic emitters.
Having reconfigured the shields on a shuttlecraft to disguise it from 20th-century radar, Chakotay and Torres try to beam up Starling from the rendezvous. Starling has a device that interferes with the attempt, but Voyager is able to redirect the transporter signal to beam him directly to the starship. Unfortunately, Starling's attempt to disrupt the beam-out damages the shuttle's controls. It goes down in the desert, where Chakotay and Torres are taken hostage by a paramilitary group. Voyager traces the crash site to Arizona, and the Doctor and Tuvok travel there to find them.
On Voyager, Starling admits to Janeway that he wants to travel into the future to steal more advanced technology. Although Janeway thinks she's put an end to those plans, one of Starling's henchmen uses his scavenged 29th-century technology to transport Starling back to his office. Outside Starling's headquarters, Paris spots a truck that appears to be moving the timeship to another location. In Arizona, Tuvok and the Doctor manage to free Chakotay and Torres. Torres repairs the damaged shuttle, which they use to track the truck and destroy it. However, they discover the truck was a ruse; the timeship is back in Starling's office, and he's just launched it.
Retrieving Paris and Tuvok, the shuttle returns to Voyager, where Janeway hails Starling, who refuses to abort his mission. She has no choice but to destroy the timeship. Seconds later, a time rift opens and Braxton appears in his timeship. With his previous timeline altered by the destruction of Starling, this Braxton has come from the future to lead Voyager back to the 24th century, where it belongs. Janeway implores Braxton to place them at Earth, but Braxton cites the Temporal Prime Directive, which Janeway cannot argue with. Back in the Delta Quadrant, the crew finds that they've gained one particular advantage from their journey: the Doctor has retained the 29th-century mobile holo-emitter, freeing him from the confines of Sickbay.