Grace brings long-running mystery to a close in tragic season finale

It did so in devastating fashion however, leaving the detective crying into the arms of his pregnant fiancée Cleo, when all was said and done.

The start of the episode picked up where the last one ended, with Roy and Cleo visiting Sandy in a hospital in Munich. Roy went in to see her on his own first, but she answers he gave him regarding her disappearance infuriated him.

Sandy revealed that she had become unhappy in their marriage, as his obsession with his work and his cases taking over, and meaning she felt she couldn't reach out to him.

Feeling she needed to make a new life for herself, she absconded - purposefully leaving Roy believing that she had died.

Furious, Roy stormed out, before Cleo convinced him to go back in, along with her.

When the subject of children came up, Sandy winced and suggested Cleo would struggle in raising theirs, as Roy would spend so much time at work.

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Roy said it was a good thing he and Sandy never had children together, and he and Cleo headed back to Brighton together, feeling they had gained some sense of closure.

However, a devastating call at the end of the episode knocked Roy completely. It turned out Sandy had taken her own life, and left Roy a letter telling him that she loved him, and that she hadn't been happy for a long time, and didn't see a way forward for herself.

She also revealed some bombshell news – she was pregnant when she left him, and the paternity test she took Roy's hair for back in season 3 was conclusive. He is the father of an eight-year-old boy, named Bruno.

She asked him to keep an eye on Bruno, which will almost certainly be a major storyline in season 5, with Roy getting to know the son he never knew existed.

It was a tragic end to season 4, which also looked as though it could end with the death of Norman Potting, when Craig Parkinson's character went undercover.

However, he made it out alive, and was last seen with the team celebrating their successful case – meaning it seems likely that Parkinson only decided to leave the series after shooting season 4, and we will find out what has happened to his character in the first episode of season 5.

You can purchase the Peter James Roy Grace books which were adapted for season 4, Dead Man’s Time, Want You Dead, You Are Dead and Love You Dead on Amazon now.

Grace seasons 1-4 are available to stream on ITVX now.

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