Lorraine Hellier returns with The Secret Mission, the sequel to The Elf King (Matador, 2017). Sweet Pea embarks on a quest, to find the Wilderness Elf clan and trade their own Moon Lake silver for the moonstones that her brother, Bay Leaf, must present to Clementine at their wedding ceremony. Sweet Pea is also tasked with finding out what happened to the human baby exchanged for Clementine, the elf changeling, whom the human couple raised as their own child.
Sweet Pea's journey takes her through the woods where she meets the Wood Elf clan. These ecological elves welcome her at their camp, but cannot help with her quest. As Sweet Pea continues her journey, she is offered support and encouragement from her ancestors through an enchanted book.
Sweet Pea's search leads her to a clan of Wilderness Elves, whose chief is a brutal and cruel Elf King. Will she succeed in her quest to find the moonstones? And what other surprises are in store as she discovers what happened to the baby exchanged for an elf?