Four new teams take off from St. Louis with a stunning twist at the starting line. Chonta discovers her southern slavery roots. Maria sees a shocking family tree. Marcus learns Arkansas is a state, and takes part in a family dance-off. The twin sisters start a texting war they can't finish.

All the teams must "smell" their way to victory competing in a blind folded challenge. A door opens, and Maria's life is changed forever. Kaley and Kristin connect with their family at a recording studio. Marcus meets his mom's brother for the first time.