I know you probably regard me as a man of iron, inured to all pain, physical and emotional. But in fact, there are limits to my endurance. It’s possible to write books that drive me away just by being too good, in terms of action and dramatic tension.

I think that’s the situation with Alex Smith’s Whip Crack, fourth in his DCI Robert Kett series. (SPOILER ALERT: If you are reading this series and have not yet finished the third book, Three Little Pigs, you should stop reading here. Parts of my synopsis must necessarily give away some of the ending of that book.)

Robbie Kett has been suspended from the force, due to the extremes he went to, to rescue his children and his wife Billie (who had been kidnapped and held prisoner 5 months). Now they’re back together, but they’re all damaged. Especially in his relationship with Billie, he’s walking on eggshells, never sure what to do to help her readjust to freedom and love.

When four young teenagers disappear in a lonely town on the Norfolk coast, his superior doesn’t order Robbie to go investigate, but pointedly lends him his holiday “caravan” (trailer) near the crime scene. He knows Robbie can’t resist this kind of case.

The four teenagers, all close friends, have been lured away from their homes by recordings on cassette players. Similar players have been left behind with messages for the investigators. With difficulty, the police are able to trace the man who bought the players, a local drug dealer. The only problem is that he’s killed himself. If they’re going to locate the missing kids, they’re going to have to solve the recorded riddles he left behind.

But there’s more to the mystery than even that. Robbie can sense something more is going on – and he’s right. I thought I had figured it out, but it was even weirder than I imagined.

Whip Crack is taut, harrowing, and exciting. The prose is good, too. I can’t fault author Smith on his craftsmanship. Also, he employs some tricks to avoid too much profanity.

But give me a break, guy. Poor Robbie has been through four thrillers now, and in each book he gets injured more – physically and emotionally – and he hasn’t been given time yet to heal up from the first book. My empathy needle is spiking here. I don’t think I can handle the next installment.

Recommended, if you’re made of sterner stuff than I am.