When Robert and Richard Johansson, III explore new surroundings in the Rocky Mountains they meet a Mountain Troll in the hills above their home. Armed with the troll queen's own machinations to infiltrate and learn whether the human race of the 21st century is ready to interact with faerie folk again after centuries apart, the little troll becomes an adopted brother to the Johansson family, and discovers more than he expected about what it is to be human.
During the course of their interaction, Robert realizes that someone from an entirely different culture, even a non-human one, can be as close as a brother. But in the end, when it is time to return Kile to his troll family and to collect the real Little Ricky, they face a serious threat from the goblins of the high peaks of the Rockies. With the help of family and friends from the small town of Maple Springs, the two Troll Brothers make their way back to the troll city and reunite both families.
Troll Brother includes a cameo by the Institution for the Preservation of Magical Artifacts (IPMA). The IPMA was first introduced in the short story, "The Old Silk Hat: A Frosty the Snowman Prequel", which is offered for free.