Imagine that Shakespeare's characters could interact off-stage and that their adventures could span beyond the bounds of the Bard's fiction: Hamlet deviously escapes from the pirates who capture him on his way to England; Macbeth's witches perform their magic on unsuspecting victims; and a shadowy figure awakes from the backstory of The Tempest. These stories and more come to life in Cauldron's Bubble, as readers explore the worlds of Shakespeare's plays with an orphan girl named Alda and a cabin boy called Dreng, who each search for something lost. Alda discovers a magical bubble that transports her to witches on a moor. Dreng, meanwhile, saves a prince. They are finally united on an enchanted island, where Alda is on a quest to free a magical being, and Dreng is smitten with a mysterious young woman. Ultimately, Alda must find power she gained in a forgotten realm to defeat a dreadful summoner, and Dreng must awaken to the realities around him before they are both consumed by magic.