(CNN) It's like a plot out of one of the "National Treasure" movies.

A stolen historic document lost to time, only to be discovered more than 70 years later at an auction.

Only thing is, unlike the Nicolas Cage movies, this document isn't a link to some sort of world-altering conspiracy.

Instead, the 1780 letter from Alexander Hamilton to Maj. Gen. Marquis De la Fayette in Rhode Island simply said "enemy" forces were coming to Rhode Island, putting the French forces in danger. The date of the letter points to the end of the Revolutionary War. De la Fayette was a French aristocrat who aided Americans during the war. Hamilton was one of the founding fathers of the United States.

The Hamilton letter, court papers say, is now in the possession of the FBI. The US attorney in Massachusetts filed a complaint with the US District Court there Wednesday requesting the document be returned back to Massachusetts.

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