Natsu and Happy always kept their true strength in secret, but after a chance encounter with a certain female, they might not need to do so anymore. Though, one bad day is enough to change ones live, including a certain Dragon Slayer. Fairy Tail has more trouble as a dark guild has declared war with them. Will they win? Smarter Natsu. OP Natsu and Happy! Strictly Natsu X OC (AU)