Gideon Sable and his partner in crime, Annie Anybody, don't want to be shopkeepers, but when Harry of Old Harry's Place retires, he blackmails the pair into taking over the shop. Before the grand re-opening, a stranger named Smith arrives and asks them to appraise a small piece of rock Smith claims holds the echo of the last siren's song. Before Gideon and Annie can find out more, Smith disappears, leaving only the stone. And then the stone is stolen.