Series by Ben Hatke. New York, NY: First Second, 2016
Jack, when taking care of his autistic younger sister Maddy, lets her convince him to trade their Mom’s car for a box of seeds. After planting the seeds their backyard becomes a magical jungle with tiny onion babies and a dragon. The dragon warns Jack to destroy the garden because there's evil underneath. And while Jack does destroy it, Maddy finds one more seed, plants it, and the adventure begins.
A Washington Post Best Books of the Year.