Episode 4

A bank is robbed of a large sum of money, and then a man turns up crucified on the moors. The Treasury calls the team in, convinced the two belong to the same case, and the pairing is pure Spooks: white-collar theft and something older and worse, side by side in the same investigation. The image of the body on the moor is the kind the show doesn't usually reach for, and it stays with you.

Harry decides the mission needs pushing further than the Treasury advised. But the push puts Danny's life in danger, and the episode is honest about whose decision that was. Danny's danger is the cost of the gamble, and the hour never lets the team forget who paid it. It's a reminder that in this show, a clever decision and a deadly one are often the same decision. Peter Firth plays the stubbornness with his usual calm, letting the weight of the choice show in the pauses.

Howard Brenton and David Wolstencroft wrote it, Rob Bailey directed. Julie Cox's Maxi Baxter, Shauna Macdonald's Sam Buxton, Daniel Kruyer's Jack Brampton and Richard Braine's Phil fill out the operation, with Keeley Hawes's Zoe and Megan Dodds's Christine Dale in the thick of it. Oliver Ford Davies's Sir Richard Bowman and Robert Hardy's Sir John Barry give the Treasury side some proper Westminster weight, and Enzo Cilenti's Carlo Franceschini is on hand as ever.

The episode works because the mystery is genuinely strange. Even when the money trail turns out to be the real story, the hour keeps the macabre detail close, and the two halves of the case refuse to sit still. The result is an investigation that feels like it could tip over at any moment, which is exactly where this show likes its people to stand.