What to read after Cassie and Lilly`s Secret?

Cassie moves from the city into the home of her Nana. Her parents are off to attend to the rainforests in South America. They often send her odd gifts and notes about how important it is to follow her heart and to protect the plants and animals around her. Cassie explores the meadow. She makes friends with the animals and learns the names of the plants. She is haunted by a face she finds, looking up at her from the pond. Although it looks just like her, it is not her reflection! The girl under the surface of the water eventually leads her to a beautiful metal gate hidden under the waterfall that cascades into the pond. The gate is locked with a padlock in the shape of a flower.