Picard, Worf, and Dr. Crusher are reassigned from the Enterprise to a secret mission. Meanwhile, the Enterprise is under the command of Captain Edward Jellico, who immediately starts making changes, much to the dismay of the crew.

Data is playing Sherlock Holmes on the Holodeck, a glitch appears and Lt. Barclay is called to investigate and he discovers protected Holodeck files. Professor Moriarty is then released and demands to see Captain Picard. Against the laws of physics, Moriarty is able to leave the Holodeck and takes control of the Enterprise.