Wyatt Bernstein is a typical boy who enjoys hanging out at the local arcade with his friend Pesto. In a household full of females, Wyatt desperately wishes for a brother he could do fun guy stuff with and who would provide him much needed male reinforcement at home. When he is reluctantly taken to a Build-A-Bestie store by his family for his birthday, he creates a boy-filled version of a Bestie. Wyatt's dream finally comes true when his creation, Crash, comes to life. 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 others back.