Geronimo's adventurous sister Thea narrates this fabulous adventure that's packed with action, mystery, and friendship! The Thea Sisters are off to New York City for another fabumouse adventure! Nicky has been training to run the Big Apple Marathon, and her friends are there to support her. While in the city, they all visit Pamela's family and have a delicious dinner at the family's pizzeria. But the mouselings discover that someone has been threatening to burn the restaurant down, and Pam's family might have to close it for good to stay safe! Will the Thea Sisters catch the troublemaker before it's too late?