Lose Track rule
The Lose Track rule is a rule covering what to do with a card when it is not where an effect expects it to be. In such situations, according to the rule, the effect is unable to move the card. This rule was officially codified in Dark Ages, though Donald X had invoked it in card rulings previously.
It is possible for a card to lose track of itself, if it has an effect that tries to move itself, which is then thwarted by another effect moving it first. For example, Hermit loses track of itself when you don't buy anything in a turn, and try to trash it and gain a Madman, but use Scheme to top-deck Hermit before you trash it. Because Hermit is not in the discard pile, where it expects itself to be, it loses track of itself, and does not trash itself.
This rule only pertains to card movement. All other effects related to the lost card still happen, as long as they are not contingent on the movement that was prevented. For example, while Scheme prevents Hermit from moving to the trash, a Madman is still gained, since the gaining of a Madman did not depend on Hermit moving into the trash. However, a Scheme that top-decks a Traveller will prevent an exchange from happening, since gaining the next card in the Traveller line is contingent on the previous Traveller returning to its pile.
 Official Rules
- In rare circumstances an effect may try to move a card that is not where that effect expects the card to be. In those cases the card does not move - the effect has "lost track" of the card.
- Losing track of a card prevents it from being moved, but does not stop anything else from happening.
- For example, if you Procession a Madman, Procession first puts Madman in play; then you resolve Madman, getting +2 Actions and drawing cards and returning Madman to the Madman pile; then Procession fails to put Madman into play again, because Procession expects to find Madman in play, but it is not there, it's in the Madman pile; then you resolve Madman again, only getting +2 Actions this time, since it says "if you do" before the card-drawing, and you did not actually return it to the Madman pile this time; then Procession fails to trash Madman since Procession again expects to find Madman in play and it is not there; and then you gain an Action costing if you can.
- Cards do not lose track of cards that they move, only cards that other cards move.
- For example when Procession puts Madman into play, that does not cause Procession to lose track of Madman; it is Madman moving itself that causes Procession to lose track of it.
- Things lose track of a card if something moves it, if it is the top card of a deck and gets covered up, or if it is the top card of a discard pile and gets covered up.
 List of cards that invoke the Lose Track rule
Cards in italics have been removed.
 Card movers
These have effects that either can lose track of a card they're trying to move, or can cause the card they moved to be lost track of by some other effect. A few of these fall into both categories.
- Royal Seal
- Noble Brigand
- Travelling Fair
- Faithful Hound
- Cursed Village
In addition, all Reserve cards and One-shots can be lost track of by any effect that tries to move them out of the play area, and all Durations can be lost track of by any effect that expects them to be discarded during Clean-up. Travellers can be lost track of if exchanged, and can lose track of themselves if moved before they can be exchanged.
For the most part, effects that reveal or set aside cards, then move them somewhere else, are not included here, as the act of revealing or setting aside a card does not (as of yet) trigger any sort of effect. Likewise, effects that only trash cards, with no other movement of the card involved, are not included. However, effects that try to set aside or trash a card after having first moved them into play or a discard pile are included.
 Cards with covering-up effects
These have effects that can cover a card on top of your deck or discard pile with a card they gain, preventing the first card from being moved.
- Border Village
- Death Cart
- Crumbling Castle
- Haunted Castle
- Sprawling Castle
- Cursed Village