Three Shells for Nikki by Philippa Norman

When Nikki arrives at Grandas house in the country for summer break, shes not sure what to expect. At first, Grandma seems a bit odd with her house full of remedies - piles of jars filled with old dried up leaves and twigs. Soon Nikki joins Grandma on the red dirt path, delivering remedies to the neighbors. Along the way she meets little Ava who needs a remedy for her cough. Nikki tries to help but her confidence plummets when she makes a terrible mistake that could have hurt Ava badly. With a horrific storm brewing, Ava is sicker than ever and Nikki is the only one who can help - but firs, she must face her fears. Join Nikki as she searches for Avas remedy in the jagged darkness of the forest, where she discovers a surprising gift and connection to her past.