Someone is leaving clementines and rotten potatoes on the doorsteps of Pineapple Port residents. After the recipient of a potato is publically humiliated on the bowling alley monitors for not fessing up to a neighborhood crime, Charlotte and Declan realize the community is being terrorized by real-life Yule Lads—thirteen troll-like brothers from Icelandic folklore who judge children "naughty or nice" at Christmas. They've thrown in aspects of The Twelve Days of Christmas too, just for good measure. Who will get the next stinky potato and why? When the death of someone close to the Pineapple Port crew suggests the Yule Lad might be tied to the sale of the community, Charlotte and Declan struggle to solve the crime before someone else suffers the Yule Lad's wrath.