In Legendary: A Marvel Deck-Building Game, players build a deck of Hero cards to battle against the cards coming from the Villain Deck and defeat the Mastermind before he can carry out his Scheme.
The Mastermind wins if he completes his Scheme. The Heroes must defeat the Mastermind four times before he completes his Scheme to win. If the Villain or Hero Decks run out of cards before the Scheme is completed or the Heroes are able to defeat the Mastermind, then the Mastermind escapes and the game ends in a draw.
A card is played from the Villain Deck at the start of every player's turn, so the Heroes are racing against the clock right from the very beginning. Some effects can cause more than one Villain Deck card to be played on a single turn, possibly reducing how much time the Heroes have to save the city and claim a victory for Good.
Inspired by the match setup info for season 4 of the Legendary Online League, which includes the Villain Deck Composition and Maximum Winning Turn Count for each match's setup, Legendary Countdown takes a given enemy setup, and reports not only the Villain Deck Composition and Maximum Winning Turn Count, but also precisely how many turns it will take for the Villain Deck to run out.