In the year 241, twelve-year-old Lina trades jobs on Assignment Day to be a Messenger to run to new places in her decaying but beloved city, perhaps even to glimpse Unknown Regions.

It's time for Samantha's summer visit again. Both she and Valerie are anxious to see if they will take another magical journey through the mirror. After learning of a problem with one of the horses, Odette makes her appearance and tells the girls it's up to them to help.

Rock, the keeper of the world beneath the world, tells about the most famous cats of the warriors Clans as well as the rogues, kittypets, and others, to three kits that have recently entered his realm.