The characters find an old scroll which describes a city called Palaodrin. In it, it says that the city had ties to the magics of the universe, as it was in the very center of the prime material plane. Surprise! After a lot of research, the characters find out that [pick a city in your campaign] is right on top of the old city of Palaodrin. If the characters explore [the city that is listed above]'s sewers, they eventually will discover the sword of Palaodrin. Make up a bunch of stats for it, find the original stats for it on the net, or I can send you mine if you ask for them.