The U.S.S. Voyager is fired upon by the 29th-century Federation "Timeship" Aeon commanded by Captain Braxton, who has time-traveled through a spatial rift to destroy Janeway's ship. Braxton claims that Voyager is responsible for a temporal explosion that will obliterate Earth's solar system in his era. Although equipped with only 24th-century technology, the crew manages to deflect Braxton's blasts and damage his ship, but then both the timeship and Voyager get sucked through the rift. The starship winds up in orbit around Earth in 1996.
Knowing Braxton's ship holds the key to returning to their own era, the crew begins searching for it, and an Away Team beams down to Los Angeles to investigate subspace readings that seem out of place in the 20th century. Meanwhile, at Griffith Observatory in the Hollywood Hills, astronomer Rain Robinson picks up Voyager's warp emission on her instruments and reports the finding to computer mogul Henry Starling, who funds her lab. Against Starling's instructions, Rain transmits a greeting to Voyager, and the crew tracks her to the Observatory. While Paris and Tuvok head for the site, Chakotay and Janeway identify a homeless man as Captain Braxton. He explains that he emerged from the time rift in 1967 and crash-landed in the desert, where a young Henry Starling found the timeship and utilized its technology to start a high-tech empire. Starling is now planning to use Braxton's vessel to time travel, and, according to Braxton, that will cause the explosion in the future.
Fearing that Rain is a security risk, Starling sends a henchman to kill her. But Paris and Tuvok spirit her away before she can be harmed. When Rain questions what they're up to, Paris tells her that they're secret agents tracking a Soviet KGB spy operation. She sees through his story, though, because the Soviet Union and the KGB no longer exist.
Chakotay and Janeway sneak into Starling's office, where they discover Braxton's timeship just as Starling walks in and confronts them. Janeway warns Starling not to launch the ship, explaining it will unleash disaster. Undaunted, Starling tries to kill Chakotay and Janeway, but they're transported to Voyager in the nick of time. They try to beam up the timeship, but Starling uses their transporter beam to access Voyager's computer and study its systems. Minutes later, the wily Starling steals the Doctor's program from Sickbay. To complicate things even further, Voyager's presence is disclosed on the evening news!