Long ago, Haruka Hoshinogawa made a wish under the town's ancient cherry blossom tree with her grandfather, who gifted her a special cherry blossom ribbon. Growing up, she cherished this present and began fifth grade at school. When the old tree started to wither, her grandfather left to explore the world, entrusting Haruka to manage their shop. One night, her beloved ribbon transformed into a Cocotama, a divine being born from cherished objects. Startled, Haruka awoke to find the Cocotama, named Ribbon, nestled in her Hiding Egg. Upon touching it, the egg morphed into a mysterious key, sparking Haruka's curiosity. Ribbon revealed herself as the key's true form, the Key of Wonders, designating Haruka as the fated Legendary Contractor of the Cocotamas. Together, they navigate running the shop, befriend other Cocotamas, and unravel the enigmas surrounding the powerful key they possess.