When the squad's rig breaks down in the field, Casey reunites with his old friend and colleague Jason Kannell from Squad 6, whose crew gets assigned a temporary change of quarters until the rig issue is resolved. Dawson and Brett serve their time in retraining, both tackling the class in unique ways. Severide tries to remedy what is going on with Anna and finds support from unlikely sources. As Connie returns from her family engagement, the crew lays bets on how long her temporary replacement Marcy will last.