Dark Frontier, Part I

After Voyager manages to destroy a Borg probe, Seven of Nine finds data nodes filled with tactical information among the debris. With it they locate a heavily damaged scout ship nearby, and Janeway decides to plan a "heist" — invade the Borg vessel while its defenses are down and take its transwarp coil, which will shave 20 years off Voyager's journey. The crew will create a diversion, then send an away team in to steal the technology. Hoping to find information that will give them a tactical edge, Janeway assigns Seven to study her parents' field notes that Voyager recovered from the U.S.S. Raven.

Once she begins studying her parents' logs, Seven remembers their encounters with the Borg. She was only a small girl at the time, but she vividly recalls their fascination with the mysterious Collective. Meanwhile, Voyager catches up with the scout ship. The sphere's shields and transwarp drive will be off-line for the next 72 hours, allowing the crew only a short time to plan the mission.

During a holographic simulation, Janeway and the others practice their mission down to the second. They have only two minutes to disable the sensor grid and transport the coil to Voyager before being detected. After leaving the holodeck, Seven is unsettled by her close proximity to the Borg, even if it wasn't real. When Naomi Wildman begins asking her questions about the Collective, Seven hallucinates that the Borg have accessed her neural transceiver and know about Janeway's plan.

Further memories of her parents' mission reminds Seven of their arrogance in underestimating the Borg, which eventually led to their assimilation. Based on the Hansens' description of a bio-dampener in their notes, the team replicates the technology in order to go undetected on the sphere. Asserting that she is willing to risk her own well-being for the sake of the crew, Seven persuades Janeway to assign her to the away team despite the Captain's reservations.

The mission goes as planned until Seven once again hears the voice of the Collective luring her back to the hive. In a sudden change of heart, she refuses to transport back to Voyager with the others, and Janeway is forced to leave her before she is assimilated herself. The sphere returns to Borg space with Seven onboard, and the Borg Queen welcomes her back to the Collective ...