Baffled and disappointed when you saw this card?
Lets put things in perspective:
-This card is an arcane item, it no longer occupies the hand slot.
-This card lets you investigate without provoking attacks of opportunity.
-If you succeed on your investigation check while using this item, an enemy is automatically evaded.
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It is really easy to misunderstand the purpose of this card:
-This is not the card that lets you evade with your .
-This is the card that lets you totally ignore an enemy at your location while you investigate.
The scenario you need this card for:
You're the clue-hoover, you pick up nearly every clue on the map while somebody else clears the way. An enemy spawns on you, it's some small fry with a half decent fight value and 2-3 hitpoints. What now? The fighter has to come running and deal with it right? Not with this card in play! You can just keep investigating, totally ignoring the threat, and if you happen to succeed in acquiring the clues you're there for (which is highly likely) you'll have evaded the enemy as well! Now if the location hasn't been cleared yet you can keep doing this for a couple more rounds if you need to.
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By far the most powerful part is the fact that this card lets you investigate opportunity attack-free. If you find yourself hard pressed by a monster (multiple monsters even) at a difficult and important location (Difficulty 4 or 5), you can use this card to get the breathing room you need to throw multiple attempts at the clues you need to close out the game.