Frank and Monica rekindle their self-destructive relationship after Frank's mother returns from prison to wreak havoc. Fiona is thrown for a loop when Steve returns from Rio with a surprise. Lip makes big changes in preparation for the arrival of his and Karen's baby. Karen and Sheila clash over Karen's new husband Jody, a good-hearted but weird guy she met in Sexaholics Anonymous. Ian tries to get into West Point. Debbie prepares for the onset of puberty. Kev and Veronica contemplate starting a family.
Fiona spends her summer with a new guy and bartending, while Debbie runs a daycare at their home. Meanwhile, Kevin realizes his extended weed-growing left him with a huge electrical bill and Frank borrows his youngest son Liam to help him pay a debt.
As Sheila conquers her agoraphobia, a worried Frank finds a new financial plan in fellow bar patron Dottie, whose declining health and city pension make her an ideal match; Fiona juggles her job, the kids and her burgeoning love life, and Jasmine tries to help by setting up Fiona with a sugar daddy; Veronica takes some old folks from the home on an excursion; Lip worries about Karen's growing relationship with Jody; Ian tries to land a recently released Mickey a job at the Kash and Grab; Debbie wants her own room; Carl moves into the van.
Fiona hopes her moral compass isn't leading her astray when she reconnects with her married high school crush, but when she finds an abandoned purse with over five hundred dollars inside, she assumes her luck is finally changing; Frank is willing to do just about anything to stay in Dottie's good graces, even marry her; after Harry's passing, Debbie becomes obsessed with death; Kevin thinks about buying the Alibi; Lip meets with a colonel to glean information for Ian about West Point; Jody asks Frank for Karen's hand in marriage.
Fiona deals with the consequences of sleeping with Craig when his angry wife shows up at the door; Debbie develops a stress-rash and Fiona wonders if she's putting too much responsibility on the kids; Sheila has made it all the way to the hair salon and Frank realizes his days in the Jackson household are numbered; no longer having sex with Karen, Lip tries to dig up dirt on Jody; Ian continues on the path to West Point; Carl house-sits with his friend, Little Hank; Ethel meets Malik, a boy on Kevin's youth basketball team.
Frank tries to claim Eddie's insurance benefits and pension, despite being a prime suspect in his death; Fiona attends a ritzy wedding with Richard and lies about her background; Lip is devastated by Karen's rejection; Carl rents Frank's room to a hooker.
Grammy Gallagher shows up on a medical furlough and tries to track down a former meth lab protege that owes her money; Sheila plans Karen's wedding reception; Fiona double dates with Steve and his Brazilian girlfriend, and discovers that Steve is married; Ethel reacts to Clyde's death; Frank discovers the identity of Eddie's insurance beneficiary.
Lip tries to get back in Karen's good graces by crafting a prenuptial agreement for her and Jody, while Ian continues to give Lip the silent treatment; Frank wants to kick Grammy out but Fiona resists until the basement meth lab explodes; Fiona is invited on a boat trip but doesn't realize Steve and his girlfriend are also attending.
With Grammy near death, Frank exits the house but walks in on Ian and Mickey locked in passion at the Kash and Grab; when Lip drops out of school, Fiona proposes a deal where they both earn their diplomas, but Lip acts out and gets himself expelled when he realizes that Karen plans to sell their baby to the highest bidder.
Monica returns to party and plot scams with Frank, but the rest of the family suspects she hasn't returned to stay; Fiona reconsiders her decision to kick Lip out of the house; Grammy's death affects everyone differently, and leaves Frank determined to make sure he gets every last penny his mother left behind; Sheila and Jody think Eddie's ghost is haunting the house.
Fiona starts to plan for her future now that Monica is back but her reprieve may be short-lived as Monica falls apart, spends the squirrel fund and gets arrested; Steve conspires to reunite Estefania with her true love so that he can be with Fiona; Lip and Ian learn the true identity of Mandy's baby; Sheila takes in a homeless crack addict.
It's a typical Gallagher nontraditional Thanksgiving that includes a suicide attempt by Monica, Carl shooting a bald eagle, and Karen going into labor; Steve agrees to allow Estefania's boyfriend to steal his identity; Ian sleeps with a businessman named Ned; Frank tries to get his share of his mother's money from his brother Clayton.