When Elizabeth first meets Simon at Westside House, he is angry and scared. She's ten and he's eleven, and like her, Simon is a war orphan. As the revolution tears through New Haven City, the two flee toward the mountains with meager food and a hand-drawn map to an old cabin. Dodging soldiers and gunfire, Elizabeth and Simon make the long, dangerous trek to reach the Emerald Mountains. The first night in the cabin, the hearth bursts into flames and they barely escape. Roused by the fire, a scruffy dwarf pops from a nearby tree hollow. He introduces himself as Taproot, then, after much complaining, decides to help them secure basic food and shelter. He renames them Elsbeth and Sim. Under the mountain man's care, Elsbeth and Sim learn about nature and survival. Taproot shows them how to gather wildwood honey and takes them to a nearby landfill where he teaches the fine art of "dump-diving." They meet Benjamin Pensworthy, an owl that has long been Taproot's ally. After an angry mother bear threatens to maul Elsbeth, Taproot issues an ultimatum. If Elsbeth and Sim wish to remain in the Emerald Mountains permanently, they must change. The hard winter looms, and the old magician fears for their welfare. Taproot uses his powers to shrink them to a size much easier to feed and hide. When they learn of the invading government's plans to destroy the valley to build a military base, Elsbeth and Sim choose to remain with Taproot and Benjamin to protect their new home. "Elsbeth and Sim" follows two children on a classic hero's journey with a twist-one that will forever change their lives.