Nana Gallagher Had an Affair

Monica returns and the Gallagher clan are in a tizzy as they try to determine if Frank is their real father. And Fiona, who is thoroughly disgusted with Monica, decides to move in next door with Steve. Meanwhile, Eddie invites Karen to a Purity Ball; and Frank uses Carl in an effort to thwart a disability worker's attempt to pull the plug on the state funds he receives.