Conspiracy

Picard is summoned to a secret meeting with his old friend Captain Walker Keel, who, with two other captains, warns him about strange orders and suspicious deaths among Starfleet's highest ranks. Soon afterwards Keel's ship, the Horatio, is destroyed. Data's study of recent orders from Starfleet Command reveals a disturbing pattern, and Picard takes the Enterprise to Earth. There a group of admirals behave oddly, and Admiral Quinn, who comes aboard, shows startling strength before Dr Crusher finds a parasite inside him. Picard and Riker are invited to dinner at Starfleet Command, where the infected officers reveal that alien parasites have taken over much of the command structure. Riker, pretending to be one of them, helps Picard fight back. They trace the creatures to their host, Lt Cdr Remmick, and destroy him. The remaining parasites die with him, but not before a signal has been sent out into deep space.