Robyn (Anna Paquin), is a hugely capable American PR executive working in London who specialises in clearing up the monumental messes caused by her hapless and selfish clients. Although utterly in command of her job, her personal life is spinning out of control.
Required to do some highly questionable things during the course of her work, Robyn is flawed but fascinating and thrives in the work environment. She enjoys close relationships with her office "family": her tyrannical boss Caroline (Sophie Okonedo), her tirelessly hedonistic colleague, Eve (Lydia Wilson), and her endlessly willing intern, Melody (Rebecca Benson). If there is media fire that needs putting out, you're going to call Robyn.
She is also dealing with a very tangled private life. Despite the fact that she occasionally slips and sleeps with her clients, she is devoted to her loving boyfriend, a nurse called Sam (Arinze Kene). He is very keen that they take their relationship to the next level and try for a baby.
At the same time, Robyn is coping with her own grief. Her mother committed suicide by jumping off Brooklyn Bridge a year ago, and Robyn and her younger sister Ruth (Geneveive Angleson) are still trying to process it. As the series progresses, Robyn also tries to help Ruth's hopeless husband Mark (Rufus Jones) out of a fix.
In addition, Robyn tries to kick her myriad of addictions. However, her life only becomes more complicated when, at a Narcotics Anonymous meeting, she finds herself undeniably drawn to the very charismatic and damaged fellow addict Tom (Marc Warren).
Written by Oliver Lansley (Whites), guest stars in Flack include Alan Davies, Max Beesley, Katherine Kelly, Rebecca Root, Rebecca Scroggs, Amanda Abingdon and Bradley Whitford.