The room was full of moon shadows and dancing light. But it was the wall around the window that Lucy couldn't stop staring at, the one with the painting of Spring. It was as bright as a sunny day and the tiny yellow flowers that covered the fields were moving, as if a breeze had blown through the painting and set all the petals dancing.

Lucy McKenzie can walk through walls. Sent to stay with her Aunt Big in a hidden valley, Lucy discovers the old house is full of mysteries. One hot night, she hears a voice calling from inside a painting on the dining-room wall.

On the other side of the painting, Lucy meets three children. Together they race horses through the bush, battle fires and floods, and make friendships that will last a lifetime. But who are April, Tom and Jimmy Tiger, and what magic has drawn Lucy to them?