3000 years ago Steve killed the Ender Dragon. He so after closed off all the portals but people wondered why. Now Dr Frank n Furter has rebuilt the portal and you must go in and find out Steves Secret. Collect all the heads and even the bonus Nether Star/ cube and Dragon Egg.
Is made for Sphax textures or Vanilla. Made by The Winter Miner, https://www.youtube.com/channel/UC-hZWxvKLQrqq5PDpNO7tgw
P.S If you do an LP of the map on youtube please post a link in the comments.