After Fiona leaves, the Gallagher house is louder, messier, and missing the one person who used to hold it together. When loud-mouthed South Side girl Tess Donnelly starts showing up through Debbie, she slips into the chaos a little too easily, and straight under Carl Gallagher’s skin. What starts as constant tension, bad decisions, and a refusal to admit there’s anything real between them turns into something much harder to shake. On Wallace Street, some habits are harder to quit than others.