Birthing Grounds is a small special mission/campaign that revolves around the monkeys responding to a distress signal to an older Bloon Factory that has been shut down due to illegal experimentation with Bloontonium. This campaign pack has a total of 5 levels, all of which use the original btd5 towers along with the old 'Corrupter Campaign' towers. (CC Towers no longer have 3rd path upgrades). The bloons that occur in this special mission pack are also the same as the ones that were once found in the Corrupter Campaign.