All minions lose Stealth. Destroy all enemy Secrets. Draw a card.
Not only does it reveal your enemies, but its also great for parties!
 How to get
Flare is an extremely strong situational card which removes stealth, destroys enemy secrets in play and allows you to draw a card. One of its strongest uses is in countering the very strong and popular hunter secret Explosive Trap. It can also be use pre-emptively if going for the kill with a large minion to prevent the use of defensive secrets such as Counterspell, Ice Block, Eye for an Eye and Misdirection. While Flare is a situational card it can be used against rogues to remove stealth and against paladins, mages, and other hunters to get rid of their secrets. Against the other classes, while they are not focusing stealth and they don't have any secret cards, it can still be useful if they use any of the neutral stealthing minions.
Flare is a hunter ability from World of Warcraft which allows the hunter to fire a small flare into a targeted area. The flare remains for 20 seconds, during which time it will expose any hidden, stealthed or invisible targets within 10 yards. Although it has no destructive abilities, like in Hearthstone Flare is the bane of anyone relying on secrets and concealment, and is one of the only ways to counteract these effects.