Seven of Nine decides to increase the amount of information she receives from the ship's database by directly assimilating as much of Voyager's data as possible. The data overload causes her to become paranoid. She suspects conspiracy and pits the Maquis half of the crew against the Starfleet half in a game of suspicions.
She uses evidence concerning possible spatial-warp technology developments to convince Chakotay that Janeway might be spearheading a Federation presence in the Delta Quadrant. She then uses the same evidence to convince Janeway that Chakotay might be spearheading a power grab with the same technology.
The two end up comparing stories and they realize Seven is acting irrationally. The Doctor determines that Seven has downloaded way more information than even her enhanced systems can handle.
Seven then starts suspecting about a third conspiracy, that the aim of the last five years was actually to grab a Borg drone, herself. Seven steals the Delta Flyer in order to escape from Voyager. Janeway manages to beam aboard. She convinces Seven that she is ill and she returns to Voyager for treatment.