Frank returns, disrupting life; Lip attends college; Ian is missing; Fiona tries to connect with Debbie and Carl.
Fiona begins to enjoy the perks of living life just above the poverty line. She uses her newly activated health benefits to take the kids for checkups. However, when a road rage incident damages the company car, Fiona tells a much bigger lie about how it happened. Meanwhile, Lip seems to have lost his mojo as he struggles in school and with the ladies.
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.
Against her better judgment, Fiona continues her secret affair with Robbie. The situation nearly boils over when Mike shows up at Robbie’s apartment while Fiona is inside. Fiona is able to hide just in time before her infidelity can be exposed. Frank, in increasingly dire health straits due to liver disease, attempts to contrive an “accident” that will provide an ample insurance payout to cover the cost of a potential transplant.
Fiona's series of bad decisions involving Robbie finally boil over. Meanwhile, Frank and Sammi pursue a cure for Frank's liver trouble and try to catch up on missed father-daughter time; and Lip gets a surprise visit at college from Army investigators.
Fiona ends up in jail; the family waits for news about Liam; Frank wakes up in the emergency room.
Guardianship duties fall upon Lip - who gets some unexpected assistance.
To prepare for a visit from her probation officer, Fiona must remove all paraphernalia from the house; Ian is kicked out of Mickey's house.
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.
Fiona violates terms of her probation, sending the family into search party mode.
