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.

Fiona is hauled off to a correctional facility. Amanda’s parents bribe Lip.

Fiona gets out of jail. Frank is feeling like his old self.

Fiona juggles her job and a crush. Lip heads back home.

Sheila gets an offer to buy her home. Plus, Fiona is off house arrest!

Frank enlists Carl to scare off the lesbians. Debbie throws a wild party.

Frank retraces the path of an epic bender. Fiona and Gus head to city hall.

Fiona's plans to announce her marriage unravel. Mickey asks for Lip's help.

Fiona is thrown into chaos by the return of Jimmy. Ian takes Mickey's baby.

Ian finds himself at the psych ward. Fiona decides between Jimmy and Gus.

Gus tells Fiona he's leaving to go on tour. Frank seeks revenge on Sammi.

Frank plays tour guide for his doctor. Fiona preps Carl for sentencing.

Frank has a ball with his new sick friend and formerly uptight doctor.

Frank grows concerned as Bianca's behavior becomes erratic and dangerous.

Fiona reunites with Gus. Frank works to keep Bianca happy. Season finale.