After 3 seasons, CBS pulled the plug on Under The Dome, their summer series based on the Stephen King novel of the same name.  Initially planned as a limited series, the ratings for the show were good enough to leave the first season open ended and to bring the show back for a longer run.  Unfortunately, the plots became more ridiculous as the show needed to find ways to keep everyone inside the dome while adding new characters who seemingly could get inside with little to no effort.  Ratings dropped for each subsequent season and, prior to the 3rd season wrapping up, it was announced that the show would not be returning for a 4th.