Twenty-four-year-old Marnie is at breaking point with her XXX-rated thoughts.
2 -Episode 2 33 min
Marnie decides to attend meetings for people suffering from sex addiction.
3 -Episode 3 36 min
Marnie is determined to make the most of being single while living in London.
4 -Episode 4 34 min
Marnie and Charlie try to pick themselves back up after hitting rock-bottom.
5 -Episode 5 35 min
Encouraged by her new therapy, Marnie confesses her secret to old friend Helen.
6 -Episode 6 35 min
Marnie is shaken when she realises she's pushed Shereen too far.
Twenty-four-year-old Marnie is witty, smart and 'normal'. Well, 'normal' apart from the relentless noise inside her head. For the past 3,723 days, Marnie has been experiencing an incessant barrage of graphic x-rated thoughts. Unbeknown to Marnie, she's caught in the grip of a remarkable form of obsessive compulsive disorder – nicknamed 'Pure O'. After vividly imagining her parents engrossed in an orgy at their 25th wedding anniversary party, Marnie packs a bag and jumps on the first coach out of Scotland. Moving to London, Marnie is desperate to find out what's wrong with her.