Saffie isn't your average naughty little sister—she's got superpowers! Emma and Saffie are going to stay with their grandparents for the summer to learn how to use their superpowers. Grandma has powers too, but Grandpa doesn't, and he definitely doesn't like the gnomes doing the gardening, or the washing-up doing itself—he'd rather play with his model airplanes. As the summer passes, the girls are having lots of fun—Emma brings a whole doll's house to life (and even learns to bake tiny cakes in the kitchen), but all Saffie wants is to cheer up Grandpa—so she decides to throw him the best party ever. What could possibly go wrong?

Gwyneth Rees is the author of The Making of May, Mermaid Magic, and The Mum Hunt, amongst others. Lydia Monks studied illustration at Kingston University. She is the illustrator of the successful What The Ladybird Heard with Julia Donaldson, and has written and illustrated several other titles such as Aaaarrgghh, Spider!, Babbit, Eeek, Mouse!, and Ooo, Ooo, Ooo, Gorilla!