Board Thread:Deltora Quest Community/@comment-10087329-20130527094453/@comment-4977079-20130826223714

I think its mentioned in The City of the Rats. Reeah talks of it to Lief while Lief is distracting him when Jasmine and Barda are stealing the Opal off it. The Ra-Kacharz purposefully caused a rat epidemic to chase the people of Hira out of the city so that the Shadow Lord could make use of it.