Signal of Pursuit is a 8th-level ritual.[Dr366:31] You enchant a door within 5 squares of where you complete the ritual. The next time that door is opened, you know, as long as you are on the same plane. Depending on your Arcana check result, you can learn more. Optional Focus: If you leave a small crystal model of the door worth at least 100 gp within 5 squares of the affected door, the ritual’s duration becomes permanent as long as the model remains within 5 squares of the door.