Smith stars as the mother of a teenage boy called Noah (Louis Ashbourne Serkis), who is accused of sexually assaulting a boy during a family holiday in Turkey.
The series will begin airing on ITV at 9pm tonight.
Promoting the show, the actress said she was drawn in by the script and said: “I read it and was gripped.
"I had to know what happened. And it instantly gave me that jelly belly feeling of, ‘What would you do in that situation?’
"Kathy is an amazing lead role. I was just instantly like, ‘Wow’, and was very honoured to be asked. She’s a great character. Fiercely loyal; fiercely protective, and someone I could relate to."
She went on to describe it as “high angst”, adding: “I instantly thought this has never been done. I’ve never read anything like this before. And from the minute Noah was arrested, that’s it. Four hours of intense, high drama.”
So, you can either watch the episodes each Monday for the following three weeks or binge-watch the entire season in one go.
Speaking to RadioTimes.com and other press, writer Danny Brocklehurst set the scene for the family's circumstances: “The Powells go on holiday with Kathy’s [Smith] sister, her husband and their young son, who has attention deficit disorder. And there is a certain amount of baggage that each character goes on that holiday with, as anybody does."
He added:" "There’s stuff going on in their life, there are cracks, there are tensions that are bothering them, but they're going on holiday hoping that the sun will smooth it all away and they’ll have this lovely holiday, and it'll all be fine and they'll come back relaxed.
"But what happens with Noah’s arrest is that all those things become heightened and the cracks intensify and they're suddenly in a hothouse environment where everything is put under this microscope."
No Return will premiere on ITV and ITV Hub at 9pm on Monday and air weekly from then on.
No Return will consist of four episodes, which will be available to watch on ITV Hub and BritBox after the first episode premieres on ITV.