Tidings Not Burdens is a set with two special promo cards - "Fly, You Fools" and "I was sent to bear tidings, not Burdens", given out with pre-orders of Warriors of Middle-earth.
These two cards provide our answer to the years-long question "Why Gandalf did not ask the Eagles to carry the Ringbearer to Mount Doom?". They are presented as Promo Cards as they introduce a funny twist to War of the Ring and are meant to be used as a "surprise" to your friends when you include these cards in a normal game - but they are playable nonetheless.
For more information, visit the BGG listing.