Voight convinces Deputy Crowley to bring in his former cellmate, Eddie Little, as a CI for the unit in order to help bring down a big-time cocaine supplier and his local dealers. Antonio is skeptical of this decision but Voight puts him at ease when he opens up about his time in prison with Little. Meanwhile, Burgess makes a difficult decision regarding her relationship with Ruzek and Roman devises a plan to help fund Platt and Mouch's wedding with the help of Firehouse 51.