Examination Day
https://www.youtube.com/watch?v=csQAmclFLJo
That is a link to the episode on YouTube. And now that you've been given the opportunity to watch the episode, I feel no need to give a spoiler alert.
I've always been confused by this episode. Why would the government murder children with higher than normal intelligence? That doesn't make any sense. Murdering stupid children sure. But not the smart kids. Why kill the smart kids?