Yume’s younger cousin Nana misses her mom too much to enjoy her playdate at Yume’s house, so Yume and her friends must keep a close eye on her.
The story begins when a middle school girl named Yume sees something fall from the sky, and meets a pale violet-colored kitten named Mew. It turns out that Mew has the power of "Yume Synchro" (Dream Synchro), the power to enter dreams. In the dream world, the girl and Mew collect Dream Stones. (Source: ANN)