After a Cheyenne foster child goes missing, Walt and the team investigate the boy's birth family on the Rez. The stakes are raised when two more Cheyenne foster boys disappear and an unregistered sex offender is reported missing. The children in the group home insist that the boys were taken by a "dog soldier," a legendary Cheyenne warrior who can change shape from man to dog. Walt knows that the kidnapper was not a spirit, but a man who he must find before the unthinkable happens.