Forced out of business when her cleaning company goes bust and her van is crushed, Mary sees the opportunity for revenge when Minister for Work Chingford Steel, on walkabout in Govan, asks to use the toilet and she takes him hostage. Initially shocked Rab warms to the situation and a siege develops with the Nesbitts negotiating for home improvements. Mary gets her job back but Rab has one more protest to make, taking advantage of his newly diagnosed medical problem.
Whilst Mary and Ella make a name for themselves as singing duo the Scrubbers,Rab and Jamesie become topless cleaners as Hunks For Hire. Surprisingly Rab helps a single parent ex-drug addict clean up her act whilst Jamesie is a hit with his gay clients. The Scrubbers,on the other hand,end up brawling in the presence of singer Susan Boyle.
With Gash back in the mental hospital it falls to Rab and Mary to throw Peaches her birthday party but Rab is late,having been summoned by Jamesie for advice,having impregnated girlfriend Irene. With an enraged Ella literally emasculating Jamesie and an annoyed Mary accidentally stabbing Rab,the two men both end up in hospital but fortunately Rab is able to retrieve his friend's missing member for surgical replacement. However,after the Nesbitts' evidence in court has got Ella off the hook,Jamesie gets a pleasant surprise.
Rab is incensed to learn that the drop-in centre where he holds his self-help group is to close for lack of funds and campaigns on local radio where his swearing gets bleeped. A planned protest to immolate himself angers councillor Simon Byrd but publicity - and drugs money - save the day. Mary,meanwhile,working as a cleaner at the golf club,is charmed by romantic customer Kendrew but soon discovers his sordid secret.
When Peaches nominates her grandfather as her role model to new school-teacher Miss Carruth Rab is on his best behaviour,even staying off the drink when the Nesbitts join the Cotters for Jamesie's birthday dinner - though the two husbands do end up in a very strange crack-house. Next day Rab comes to school to give his speech,only to find he and Miss Carruth are in the same AA group - though she does him proud by praising him to Mary and head-butting the snooty headmaster.
With Gash rehabilitated to his parents' house Mary wants Rab to set a good example and give up the drink but,egged on by Jamesie,he succumbs and causes a scene in church,getting ejected by Vivian Biddulph,the new English female vicar. After Mary has made him apologise Vivian lets him back in,providing he shows repentance by sitting on the humiliating cutty stool. Rab refuses but,when bigots threaten to drive Vivian away,he lurches to her rescue,delivering a speech on true Christianity - before getting in a fight with Gash.