Dog's journey. Beloved dog Bailey is given an instruction by his boy Ethan -- no longer a boy -- to protect Ethan's granddaughter CJ at any cost. Again, Bailey takes this command to heart, through several lives, always finding his way home no matter what. Dog's purpose. It shares the soulful and surprising story of one devoted dog who finds the meaning of his own existence through the lives of the humans he teaches to laugh and love.