This Spanish import presents the day that three mice find a key and speculate on what it might unlock. When the Mouse brothers emerge from their cheese-shaped house in the forest, each has a different idea about how to spend their Saturday. The oldest wants to pick apples, the middle one prefers poppies, and the youngest wants "that little piece of the sun that's fallen onto the ground!" Realizing the "little piece of sun" is really a key, the siblings imagine opening a pirate chest or a castle door, but the smallest mouse decides "it must be the key to happiness!" Since the mice don't know how to find the happiness it unlocks, they go home to consult their mother and discover her searching for this very object. Connecting the themes of their play, they posit that their dwelling holds treasure, compares to a castle, and is filled with joy. The story suffers from a trite ending, predictable plot, and (for the most part) pedestrian language: "It's a very old key; I'm sure it opens the door of an old castle!" The illustrations, which appear to be digital, are stronger. Padrón's close-ups are so revealing that readers can view tiny mouse hair in the profiles. He creates a successful depth of field with mist-shrouded trees in the background and warm, textured images in the foreground. The accomplished art, however, does not compensate for the story's lack of suspense, humor, or lyricism. (Picture book. 3-5)

PreS-Gr 1 When three mouse brothers head off on an adventure, the youngest one finds "a little piece of sun," which turns out to be a small golden key. The siblings take turns imagining what use the key might have. Does it open a pirate treasure chest or the door of an old castle? Is it the key to happiness? This simple story with themes of family and fantasies is smoothly translated from Spanish. Padrón's stylized images provide varying perspectives, with the mice sometimes shown as shadows racing through the forest and sometimes in close-up views with colorful noses that match their striped shirts. The forest includes a triangular cheese house with a blue door, and tree branches sporting cheese leaves.