"The Chase" is the 146th episode of the syndicated American science fiction television series Star Trek: The Next Generation, the 20th episode of the sixth season. It is directed by series cast member Jonathan Frakes (Commander William Riker). Set in the 24th century, the series follows the adventures of the Starfleet crew of the USS Enterprise-D. In this episode, four competing expeditions—Federation, Klingon, Cardassian, and Romulan—attempt to solve an ancient genetic puzzle. Plot Captain Picard (Patrick Stewart), who has always been a student of archaeology, is visited by his former mentor, Professor Richard Galen (Norman Lloyd). Galen, who Picard said is "like the father who understood me," states that he has come across something in his travels which could be the most profound discovery of their time. However, Galen will not tell Picard about what he has found unless Picard agrees to go with him, which means leaving the Enterprise and his career in Starfleet behind. Picard ultimately declines, although he is torn about disappointing his former mentor, who angrily remarks that Picard's job was like that of "A Roman centurion .... maintaining a dull and bloated empire." Shortly after leaving the Enterprise, Galen's transport vessel is attacked and boarded. When the Enterprise arrives, a critically injured Galen is beamed to Sickbay and, before he dies, he apologises to Picard for his earlier rude remarks. Picard decides to investigate Professor Galen's research, an investigation of Galen's ship yields no results other than a series of seemingly random number blocks. After studying the ambiguous number blocks for hours, the discovery is made that these fragments are compatible DNA strands which have been recovered from different worlds all over the galaxy. The crew eventually believe that they have discovered an embedded genetic pattern that is constant throughout many different species, and it is speculated that this was left by an early race that pre-dates all other known civilizations. This would ultimately explain why so many races are humanoid. Picard resolves that the answer to the 'puzzle' will be revealed when the remaining DNA samples are obtained, and so the Enterprise travels to a remote, uninhabited planet that Galen had mentioned was his next destination. They encounter Klingon and Cardassian ships that appear to be on the same trail, each group believing the puzzle will yield the design of a formidable weapon or the secret of an unlimited power source, respectively. The Enterprise