Roller coaster ride

"Seb, Princess, and Snowy are the three horses who call themselves the Tres Caballos Incognito, and they like to break out of the barn at night and go on adventures--and tonight's adventure is a trip to an amusement park where Seb the draft horse is looking forward to riding the roller coaster, and gathering more material for the book he is writing"--OCLC.