The series centres on Robert Hendy-Freegard, one of the UK’s most notorious conmen – who was born in Dronfield and reportedly lived for a time in Hillsborough.
The true crime documentary reveals how Sandra met Robert on a dating website in 2011.
The programme reveals how her children, Jake and Sophie, noticed their mother becoming distant before taking off and leaving – and they’ve reportedly never seen her in person since.
Sandra is said to occasionally contact her two children, but has never disclosed her current location to them.
During an appearance on Good Morning Britain, Jake revealed he and his sister have not seen their mum for several years.
He said: “I would love to see her again and I would love her to see the real truth.”
Sophie added: "We were young, we were just living our life with our mum and she did everything for us. [We were] very close.
"She worked hard, she always did everything for us and was extremely devoted to us and no one can ever question that which makes everything that’s happening now so out of character.”
Jake made a desperate plea for his mum to return and said: “I just want to say that we both love you, we miss you and we want you back in our lives.”
All episodes are available to stream now on Netflix.