It's a Ranger Day and Tom and Twigs are keen to earn their Super Helper badges. Offering to help everyone who asks, when they ask, they quickly become overstretched to the point of breaking. Put in charge of Treetog's prized sap-root plant, they fail in their duty of care, allowing it to grow rampantly out of control. As the sap-root searches out a source of food in the caverns, the very foundations of Treetopolis are put at risk.