This was a dull episode with little in the way of redeeming qualities. Oh yay, Tasha’s sister (who we’ve never heard of before) turns up. Then there’s an interminably long sequence where she builds trust and a relationship with Data, and then she betrays everything.
I think the idea was doomed from the start – just not enough in the basic idea to make it work. But the casting of Tasha’s sister simply didn’t help, she turned in a very poor performance.
The most disappointing bit about this: this is the 80th episode of TNG, and so with the airing of this episode there were more episodes aired of TNG than of the Original Star Trek.
187 down, 550 to go.