6. Terra Pericolosa

Complete story — includes the ending

Joan returns from Denmark. Kitty is called to a museum, where valuable old maps and a security guard are missing. The guard is dead. One particular map was the target; the rest were taken just to camouflage that fact. That map, "The County of King James, Virginia, 1794", was loaned to the museum by a now-deceased member of the Bray family decades before. The family's charitable organization still exists, and is run by Margaret Bray. The thief is ex-cartography student Stuart Zupco, who turns up dead. The missing maps are found at his framing shop, but the Bray map is a forgery. It and the original are almost identical, except the course of a section of a river has been altered. That one change provides the motive. A billion-dollar casino, envisioned by real estate mogul William Hull, is to be built on land affected by the alteration. Bray's family owns property neighboring the site; the casino would send the value of the surrounding real estate sky high. Bray was the killer; without the map change, the project would have to be abandoned.