Mew is a light violet stuffed kitten created by doll-making fairies in a world above the sky. She was born on February 26 and her favorite color is pastel pink. One day, Mew fell from the sky and was picked up by a middle school girl named Yume. The girl hugged Mew and spoke to her every day, and out of a desire to express her gratitude, Mew made a wish to the moon. The moonlight made the star-shaped pattern in her ear shine, granting Mew the ability to speak. From that night on, Mew and Yume were able to talk and, when they slept together, share the same dream where they could play and exchange secrets.

Mew is gentle, kind, and warm-hearted. She loves taking leisurely walks through flower gardens and has a talent for finding sparkling, pretty things. She enjoys having secret conversations in dreams about fashion, love, and the events of the day, and she is in the process of learning dream interpretation. Her personality is supportive and caring, and she delights in being a close confidant to Yume.

Mew serves as the Dream Partner of Yume, and together they form a pair known as Dream Partners. Their main mission is to collect Dreamy Stones, which can be gathered by entering dreams using a power called Dream Synchro. This ability allows Mew and Yume to travel into the dreams of others, where they help resolve emotional conflicts, overcome worries, and strengthen bonds between people. The Queen of the Miracle Dreamy Kingdom appears in Yume's dream and explains that if they collect enough Dreamy Stones, she will grant one wish. Mew is therefore central to the story's core quest, accompanying Yume on her daily adventures and helping her navigate school life, friendships, and personal challenges.

Mew's most important relationship is with Yume, her partner and best friend. The bond between them is built on mutual trust, affection, and shared experiences both in the waking world and in dreams. Mew also interacts with other Dreamy Mates, such as Peko, a plush who loves food and making others laugh, and Suu, a clever and gentle plush who wears glasses. These characters were made by the same fairies and share the same world. There is also Yuni, a mischievous plush who creates his own companions named Tsugi and Hagi, and later a baby plush named Chia falls from the sky and is taken into Mew and Yume's care. Mew's relationships with these characters develop as they learn to work together, support each other, and resolve conflicts that arise from Yuni's pranks or external threats.

Over the course of the story, Mew grows more confident in her abilities and takes on greater responsibilities. Initially a simple, grateful plush, she becomes a capable and reliable partner who can use her powers in more advanced ways. When new enemies appear and Yuni's mischief escalates, Mew and Yume discover that they can access a stronger form of Dream Synchro called Mewkle Rain-Bow, which requires the combined power of all their friends and allies. This represents a significant milestone in Mew's development, showing her ability to unite others and protect the peaceful daily life she cherishes.

Mew's most notable ability is Dream Synchro, which she performs with Yume using a Dreamy Compass and the Mewkle Star. This power lets them enter the dreams of any person, where they can move freely and interact with the dreamer's subconscious. Mew can also communicate telepathically with Yume during these synchronized dreams and is able to sense emotions and intentions within the dream space. Her star-shaped ear mark is the source of her magical energy and functions as a key symbol of her connection to the moon and to the fairy world. Beyond her dream-related powers, Mew is a talking plush who can move and express emotions like a living being, making her a unique bridge between the human world and the miracle dream world above.