A brand new petting zoo has just opened in River Heights, and eight year old Nancy Drew cannot wait to see the animals. The star of the zoo is an adorable Shetland pony named Buttons, who has a very special talent for escaping his pen. Buttons keeps showing up on front lawns all over town, happily chewing on the neighborhood flowers. While Nancy secretly hopes the cute pony will visit her yard next, she knows it is dangerous for Buttons to be wandering the busy streets alone. The zoo owners are completely baffled because they cannot figure out how the tricky pony keeps getting out. It is the perfect case for Nancy and her best friends in the Clue Crew. You will get to follow the young detectives as they search for hoof prints, examine fences, and set up a stakeout to catch the four legged escape artist in the act.