For as long as Heidi can remember, her mentally challenged mother has had only 22 words in her vocabulary, and the precocious 12 year-old doesn't have a problem with that. Bernadette, their loving neighbor, provides them a bubble of love and protection. Then, a new word pops out of Mama's mouth - the mysterious soof - and it changes everything. Heidi is propelled on a solo cross-country journey of discovery and loss, truth and identity.