From Shadow Era Wiki

Seek is a keyword ability in Shadow Era, first introduced in Lost Lands.

This ability allows the player to search their deck for a certain type of card (e.g. an ally of a particular alignment) and add that card to their hand. This can only be done if the player has space in their hand to add that card (so a player with the maximum of 7 cards in their hand cannot Seek a card). When a card is searched out with this ability, it is revealed to all players, placed in the player's hand, and the deck is shuffled afterwards.

This ability is intended to allow players to gain increased reliability of getting the cards they want into their hand when they need them.