Hey guys I'm also after what an episode is. It was in a high school and there was 8 or so kids and there was nothing outside the windows, doors except for white. They couldn't escape. One kid had planned on killing someone earlier that day when things were normal. Later on, aliens turn up saying they have to vote someone to be killed by the end of the day. It ends up being a test. I saw it on TV ages ago and really liked it but can't seem to track it down.