Frank goes missing and turns up in Toronto, tries without success to embrace sobriety, and bends the law to protect his disability checks. Fiona falls for Steve, a handsome player with a nice car, a fat wallet, and a big secret. Ian embraces his sexuality, much to the chagrin of his brainy brother Lip. Debbie goes too far at a child's birthday party. Monica shows up with an announcement about baby Liam.
Drunken father Frank is of no use to his dysfunctional family; Fiona meets a handsome stranger when her purse is stolen; Lip is shocked to discover his brother Ian is gay and tries to hook him up with a willing neighbor.
Frank has a drunken run-in with Karen's father and takes it out on Ian. The family starts a manhunt when Frank is nowhere to be found on disability check day.
Fiona turns her attentions to Tony, a cop who has had a crush on her since childhood, but Steve isn't willing to give up without a fight; Ian is targeted by the brothers of a girl he spurned; the whole family searches for elderly Aunt Ginger, who owns their house.
Debbie, sad and lonely after Aunt Ginger leaves, steals a little boy from a birthday party. In classic Gallagher style, the family hatches a plan to return the toddler safe and sound without attracting attention from the Chicago Police Department, who has made the kidnapping a top priority. Karen, in complete defiance of Eddie, starts to tease Frank sexually. Frank not knowing what to make of it keeps himself busy with booze, picking up Sheila's meds from the pharmacy and concentrating on finding the missing boy. What began as an innocent lie for Kevin to protect himself from a hot girl ultimately becomes a proposal of marriage for Veronica.
When the Gallagher's find out Veronica comes from a wealthy family, they try to scheme a fake wedding for the dowry. Meanwhile, Frank gets some bad news about his health.
Fiona tries to prove the Gallagher home is suitable for rehabilitating a delinquent after receiving a letter from Carl's teacher; Lip gets busted taking the SAT for fellow students in exchange for cash; Kash and Ian are ashamed at their failure to stop a string of robberies at the Kash and Grab; Frank's poor business acumen continues to have negative consequences.
Frank gets into trouble with two goons he owes money. Fiona asks Sheila to take care of Liam while she spends a night with Steve, and Ian tries to stop Mickey from bullying Kash.
Sheila fears to lose Frank when he gives up drinking. While Lip suspects their dad hasn't changed, Debbie and Carl enjoy having Frank back in their life. Meanwhile, Fiona tries to find a better paying job.
Monica comes back when Frank needs her to sign documents and decides to take Liam with her. Meanwhile, Steve and Fiona move together.
The children's paternity is put into question and Frank needs Carl's help.
Tony comes closer to discovering what Steve is doing, while Fiona makes a new friend. In the meantime, Lip helps Ian look for his father.
Steve tries to convince Fiona to skip town with him now that his true livelihood as been discovered; Frank and Karen's secret is revealed, forcing Frank to go into hiding; Fiona tries to figure out how to get Lip and Ian out of jail after their arrest for car theft.