The Descent: Journeys in the Dark (Second Edition) Wiki
Defensive Position
3 Threat to Purchase
Exhaust this card at the end of your turn and choose 1 tile; place a threat token from the supply on that tile as a reminder. While this card is exhausted, each time a hero spends movement points to enter a space on the chosen tile, he must spend 1 additional movement point.
First Legion 7/12 2 Threat

Defensive Position is a Plot Card that allows you to choose any one tile on the map, and as long as Defensive Position is exhausted, a hero must spend an additional movement point to enter any space on the chosen tile. What’s more, Defensive Position doesn’t refresh like normal Plot cards — it refreshes whenever there are more heroes than monsters on the chosen tile. By massing your monsters on a key tile and fighting tooth and nail to protect it, you may significantly slow the heroes’ progress.[1]