As I was watching the Hobbit movie this past weekend, I realized how much of a retcon J R R Tolkien did in the Lord of the Rings vs the Hobbit. Retcons (retroactive continuity) have been a staple of comic books for years. Essentially they take the history of a character and change it. They do this by keeping much of the established history but use that history as a spring board to reveal new bits of that character's history that alter facts and assumptions. One of the most famous retcons was Sherlock Holmes and his "death" at Reichenbach Falls and the subsequent reveal that it was all faked.
And you can do this sort of retcon with our own campaign. If your players have moved off your plotline, you can use a retcon to move them back. If you want to introduce a completely new plotline, a retcon can be used as well. Here are a couple of ideas...
-The object. The players have something in their possession that is more than it seems. They have an object that is an artifact or other plot device to move the players into a certain direction. This object could be something as simple as an innocuous item, such as a belt buckle, or something waiting to be important, such as a plain sword. Such items can be revealed to be more than what they seem to be. Much the same way the ring of invisibility became the One Ring.
-The person. A person's background can change as well. A character may have been adopted (or found on a doorstep) and never been told the truth by their "parents". They could have had a "curse" placed on them as a child, which no one ever spoke of. Thus they could have any lineage your plot needs to move forward; they could be a lost prince, the scion of a line of seers that can see the hidden parts of your plot or have the unique ability of wielding a needed artifact. While Tolkien doubtlessly knew Aragorn was the King, no one else did. Aragorn's lineage was revealed much later in the books, something a DM can do later in their own campaign.
The next thing to consider is how the players find out about this retcon. While a DM could simply state the retcon as new fact, it is best to reveal this during play in a manner that makes sense. Often this means dealing with a rare or unique situation that causes the new fact to be revealed. Here are a few of ideas...
-Reactant. The object reacts to a catalyst such as being placed in fire, brought near another object or person. This would have to be something the object has not come in contact with thus far in the campaign. The object, or person, could begin to glow, make a noise, sparkle or anything noticeable.
-Reaction. Something rare reacts to the object or person. Maybe a newly met creature howls when the object or person comes near. Maybe an NPC recognizes the object or person as being more than it is. If your campaign can afford the time, you could have the reaction remain
mysterious; the characters know something is reacting to them but they
don't know what is causing it.
-Chain Reactant/Reaction. Maybe the object/person causes a reaction, but not until it has come in contact with a reactant. For example, a sword begins to glow when it around orcs, but not until after it has been bathed in flame. This method can be used if you want the object to react to something that is fairly common but that the party has already had contact with.
Of course, one question to ask is, why even bother with a retcon? Why not simply have the characters find the special plot device in the treasure pile of the next monsters the party kills? After all, Frodo could have found the One Necklace in the back corner of a closet. The quest then becomes one about destroying the One Necklace before Sauron can get it back and rule Middle-Earth forevermore. And yet...it is so much cooler that Frodo got the One Ring from Bilbo and an earlier adventure. It builds continuity, even if there was none before. After all, a retcon is the rewriting of history to allow for believable continuity. Players will think their past actions have consequence and meaning for what is happening currently in the campaign and what will happen in the future. Players like that level of empowerment.
We can learn from JRR Tolkien and his retcon.