S3, E5: Lieutenant Casey (Jesse Spencer) deals with the fallout of his sister Christie’s (guest star Nicole Forester) impending divorce. Meanwhile, Dawson (Monica Raymund) and Mills (Charlie Barnett) settle into their new roles at Station 51. Elsewhere, Brett (Kara Kilmer) can’t decide if she wants to leave Chicago and the Molly’s crew still can’t figure out how to get the food truck started.