Hugh Bonneville, Eric Stonestreet, Bonnie Hunt, Cary Elwes, Dean Norris and Ruth Connell have been summoned to Sofia The First‘s court to lend their voices to a special story arc that is set to debut October 12 on Disney Channel and Disney Junior. Hunt and Stonetreet will reprise their roles as Aunt Tilly and Sofia’s flying horse Minimus, respectively, in the four episodes, which will feature an appearance from the latest Disney princess to guest star on the hit series, Brave‘s Merida (Connell). Bonneville will narrate throughout the arc, Sofia The First: The Secret Library, while Elwes will voice the nefarious Prince Roderick and Norris will play Minimus’ brother, Mazzimo.

Disney is priming the pump for the special episodes with an illustrated storybook and e-book hitting shelves and online, respectively, today. Sofia the First: The Secret Library introduces the tale of how Sofia becomes storykeeper of magical books without endings and now must pursue adventures that will finish the narratives. A full-length preview and game debuts on WATCHDisneyJunior.com and the WATCH Disney Junior app October 5 and an accompanying app will be released October 8.

In April, Disney Junior renewed Sofia The First for a fourth season, and its spinoff Elena Of Avalor is due on the network next year.