Two Puerto Rican tree frog siblings learn about science and social studies topics during their adventures on their island home in this chapter book series. It's time for Carnival! Puerto Rico's joyous holiday is full of sights and sounds to explore. Rosi is determined to show Rafi the best way to enjoy the parade, while Rafi has a plan to make his sister queen for a day. But when Rafi scares Rosi with his terrible vejigante mask, Rosi decides it's time to teach her brother a lesson. This little sister has a few tricks up her sleeve too! In this chapter book series, Rafi and his younger sister, Rosi, explore their surroundings and learn about the traditions, plants, animals, and environment of Puerto Rico. Young readers will enjoy the adventures of these curious siblings and will relate to their special bond as brother and sister. An added plus, in the English editions, is the sprinkling of easy Spanish words that add flavor to the stories.