As the only boy in a family with a mom and three sisters, Wyatt Bernstein is not pleased when he is taken to a Build-A-Bestie store so he can build a customized doll for his birthday. At his wit's end, Wyatt blows a gasket and creates a boy-filled puppet he names Crash who comes to life as the brother he always wanted. Together, the new "brothers" help each other navigate life's experiences. Crash helps Wyatt come out of his shell and Wyatt introduces Crash to life as a kid. Although they sometimes have their differences, like true brothers, they always have each other's back.