<P> An energy - based lifeform from the Beta Renner cloud was accidentally trapped aboard the Enterprise later in 2364 . It initially inhabited Lieutenant Worf's body, but next moved to Crusher . It controlled her for a brief period of time, attempting to learn how to use the Enterprise navigational systems in order to return home . The being then transferred itself to the ship's computer system, then took control of Captain Picard . </P> <P> In mid 2364, Captain Picard invited Crusher on a holodeck adventure set in the fictional world of Dixon Hill . They were joined by Data and ship's historian, Whalen . Unfortunately, a malfunction in the holodeck systems due to a Jarada scan caused the safeties to become disengaged, trapping the group at the whim of Cyrus Redblock . They were later freed, but not before Redblock shot Whalen and threatened to kill Beverly . </P> <P> Doctor Crusher was offered a position as head of Starfleet Medical in 2365 and left the Enterprise during that year . She was replaced by Dr. Katherine Pulaski . While at Starfleet Medical, she decided to return to the ship as soon as it was allowed the following year . </P> <P> The reason for Beverly's return was never explicitly stated . </P>

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