Frank returns, disrupting life; Lip attends college; Ian is missing; Fiona tries to connect with Debbie and Carl.

Frank stalks his previously unseen daughter, Sammi, and is surprised to find out she has a son, Chuck. Meanwhile, Fiona and Mike are getting serious. Also, Carl begins stealing dogs and holding them for ransom so that he can earn some drug money for Frank. Sheila has her first successful online date with Native American cowboy Roger Running Tree.

Carl connects with a girl in detention; Lip and Amanda grow closer; Sheila returns with big plans; Fiona searches for a job; Mickey spends time with Ian.