The subject of the spell is surrounded with an invisible aura that anticipates and delays the teleportation of any creature into the spell's area. Any teleportation spell or effect (including all spells with the teleportation descriptor) can be anticipated, making the spell's recipient instantly aware of the exact location where the teleporting creature will arrive (subject to the restrictions below), the creature's size, and how many other creatures (and their sizes) are arriving with the teleporting creature. The spell also delays the arrival of the teleporting creature by 1 round (so that it arrives on its initiative count immediately before its next turn), generally giving the recipient of the spell and anyone else made aware of the information 1 round to act or ready actions. The teleporting creature does not perceive this delay.

Since a teleporting creature doesn't necessarily arrive at the precise location it intends, the spell also functions against a creature that arrives in range even though its intended destination was elsewhere.

For a creature that intends to teleport into range but inadvertently arrives outside the spell's area, the spell gives the recipient awareness that a creature has attempted to teleport into range and delays the creature as normal, but doesn't give any awareness as to the actual location of its imminent arrival.

The spell has no effect on creatures attempting to teleport away from the spell's area, though if their destination is within the area, the spell will affect their reentry as normal.