History Lesson Summary . After getting the coordinates from Chancellor Lomac , Commander Riker and Lieutenant s Yar and Data beam down to the surface of the planet . As they do so , La Forge picks up an energy reading on the surface , some kind of pulse that has since vanished . Captain Picard checks on the status of the away team , and Riker reports that they ' re waiting for their escort . Picard gives him a quick update and tells him to be alert . A man approaches them and introduces himself as Edic . Data comments to Edic that he is intrigued about the Tigan ' s Gravimatrix , a microscopic black hole being used as a power source . Data notices Edic ' s " interface , " a surgical implant that allows communications to be directly beamed into the brains of the Tigans . He introduces them to the Chancellor , Kadec . Riker expresses confusion because they were contacted by Lomac . However , Kadec has never heard of Lomac . Data checks a console and discovers that there is no record of Lomac and that the order of the Tigan flag has changed . On board the " Enterprise " , another energy pulse is detected and Worf declares that they are under attack . Just as Picard orders red alert , the ship is hit by something . Further investigation by Data discovers that the computers were hit by a low - grade gravimetric pulse at the same time as they beamed down . He suggests that someone may have rewritten the Tigan history and that these pulses have occurred ten times in the previous two hundred years , six times in the last ten years alone . As Riker decides to ask Kadec about it , he is hit by a beam from a graviton gun . After the three Starfleet members are disabled , a Tigan introduces himself to Kadec as Lomac . On the " Enterprise " , La Forge tells Picard that even at full warp power , they cannot counteract the force of the pulse . Worf notes that they will end up in the Gamma Quadrant soon . Picard contacts engineering and tells them to increase speed to full warp and add it to the momentum of the wave , allowing them to slingshot around and travel back in time to Tigan . On Tigan , Data ' s positronic brain is being accessed by Edic in a library while Kadec looks on . Edic tells Data that the first time they tested the Gravimatrix , it set off a pulse and that they ' d lost everything on their computers . They began to input the information by hand again , and there were some that thought that they could make things better . Data asks what will happen when someone decides that Kadec should be revised . Kadec cuts him off , telling Edic to finish rewiring Data ' s brain so that it can be updated to make him think that his time there was pleasant . In a cell , Yar has modified her combadge and tells Riker to distract the guard . When the guard brings food in , Riker distracts him as Yar sets off her combadge , filling the area with a loud squealing noise . In space , the " Enterprise " suddenly appears in orbit and fires a phaser at the planet , slicing their shield generator apart . At the same time , Riker and Yar arrive at the library and threaten Kadec . Edic shows up with a number of Tigan soldiers . He places " former Chancellor " Kadec under arrest for crimes against the state and thanks the Federation members for their time . The away team beams back to the " Enterprise " . Later on , Yar comes across Data in the conference room , standing in the dark staring out at the stars . He comments that Santayana said " " those who do not learn from history are doomed to repeat it " " and wonders whether his quest to become Human is worth the trouble . Yar offers to stay with him for a while . Memorable quotes . " " Keep your eyes open , sir . " " " " I always do lieutenant – I would not be able to see , if I did not . " " " " If we do not act soon , we will end up in the Gamma Quadrant . . . and I , for one , do not wish to go there . " " " " The exact time dilation will require a one in a million calculation captain . Even if we succeed , we will have only one chance to disable their shields . " " " " Then I suggest you start brushing up on your math , Mr . Worf " " " " Yes , sir . " " " " . . . did anyone get the name of that Sehlat ? " " " " Welcome back , Number One ! And well done . " " " " Thank you , sir . It ' s good to be remembered . " "