This is a story of Doorkeepers, people with the special ability to see, materialize and open secret doors hidden all over the world. You follow the story of Nichola and Nathaniel, students of Professor Ellie. Nichola is a quiet, gentle girl that believes everything is fine from the looks of things, but when Nathaniel suddenly turns and murders their mentor out of nowhere, Nichola has to use her powers in Doorkeeping to entrap him and find out what his motives are.