"Team Unihorn (and Woolly) is excited to enter Burlap Beach's sandcastle competition, the perfect activity after saving their home not once but twice. As the crew gets to work, Woolly discovers a tooth-shaped rock that Raina is sure is a real tooth. To settle their argument, Woolly puts the tooth-rock under his pillow that night...and wakes up to find it replaced with a shiny gold coin! Raina knows she's struck gold and quickly sets out to get more money from the ToothFairy with any tooth-shaped item she can find. But when the fairy turns out to be a Megalodon upset that the tooth is fake, Team Unihorn (and Woolly) must rescue the beach yet again."--Provided by publisher.