1. IT GOES BACK AND FORTH IN TIME
Catherine Cookson sagas tend to be plotted in a conventional way. They take the time to set up the characters and then follow them through their various misadventures, the themes unfolding slowly and clearly. But things are very different with The Secret, which begins decades before the real story, right in the middle of a darkly mysterious scene (a boy is given money by a frantic man while a woman gives birth nearby) and then cuts forwards in time without any explanation. We're left chomping at the bit to find out more about our hero Freddie Musgrave and his shady past, but we have to be patient because the story will unexpectedly go back and forth in time to reveal the truth bit by bit.
2. IT'S GOT A TRULY SCARY VILLAIN
Conflict features in every Cookson story, but while the villains can be nasty, they're usually people we can recognise from everyday reality. Think stern, overly controlling fathers, bitterly vengeful servants, scheming businessmen, power-hungry wives, or common street crooks. The Secret is very different. Its main villain is a flamboyant monster of a man whose twisted motivations and mood swings make him seem more like the baddie from a Hollywood thriller or horror film than the usual, down-to-earth Cookson adversary. We won't say who he is in case you've not watched it yet, but rest assured you'll almost want to boo and hiss whenever he's on screen, particularly during the pulse-pounding finale.
3. IT'S GOT A MACGUFFIN
A term popularized by movie maestro Alfred Hitchcock, a MacGuffin is an object which exists in a story only to motivate the characters and drive the plot forwards. The identity of the object itself is actually irrelevant - it's just the spark that gets the story going. MacGuffins turn up in lots of thrillers (often in the form of a secret treasure, a mysterious briefcase, or a missing microfilm), but not so much in Cookson dramas. And yet The Secret gives us a proper MacGuffin in the form of a stash of rare diamonds which turn up out of the blue to excite and perturb various characters, including our hero Freddie Musgrave and dodgy criminal Mr Freeman. Its existence is a tell-tale sign that we're squarely in thriller territory.
4. IT'S ACTION-PACKED
Well, it's action-packed by Catherine Cookson standards anyway. While you do see characters come to blows in plenty of her sagas, The Secret has an unusual emphasis on physical drama and dynamic action sequences right from the start, whether we're seeing young Freddie running swift errands for his criminal bosses and freeing a child from captivity, or a sudden murder being frantically covered up, or Belle being imprisoned like a damsel in a gothic fairy tale. The fight scenes are directed with heart-thumping impact, while the closing moments will have you perched on the edge of the sofa. Who knew Catherine Cookson could be like this?