After the magical realm of Niko Garden is attacked, its animal inhabitants are corrupted and turned into eggs. One day, in Animal Town, where humans and animals live together, middle school student Iroha Inukai is walking her family's dog Komugi, who finds a strange stone-like object. When one of the eggs hatches into a monster called a Garugaru that begins rampaging, Komugi's desire to protect Iroha resonates with the Mirror Stone and causes the stone to turn into a Wonderful Pact, which grants her the power to become human and transform into a Pretty Cure. She purifies the Garugaru and turns it back to its original form: a Niko Animal named Mey Mey. He tells her and Iroha what happened to Niko Garden and that they must purify the Garugaru and return them to Niko Garden. Together with Iroha, Yuki, and Mayu, Komugi works to save the Garugaru and Niko Garden.