Katherine Winter (Hilary Swank) is a former Christian who, after suffering a great tragedy on a mission in Africa, has established a career investigating and debunking miracles. Along with her assistant Ben (Idris Elba), she travels to the Louisiana town of Haven when the local river turns blood-red. Instead of discovering a natural phenomenon she finds herself in the midst of a series of Biblical plagues and a town guarding a hidden secret.

The Reaping boasts a great cast, a talented director and some impressive production values. It is important to note that from the outset, because those specific merits are easily lost by the film’s ham-fisted, cliche-ridden and wall-to-wall dreadful screenplay. There have been some great horror films made out of Christian theology. A few, like William Friedkin’s The Exorcist, stand as genuine all-time greats of cinema. The Reaping has no chance of following them, or even managing to reach their shadow. It is less of a thriller and more of a long, tedious list of things not to do in a horror movie.

For one thing it foreshadows its story aggressively, resulting in pretty much no surprises whatsoever. Had it concealed its tracks a little better it could have climaxed on a tremendous bait-and-switch, but instead it just confirms what most of its audience will have already guessed.

It also leaves little room for doubt between whether the phenomena affecting Haven are measurable scientific occurrences or if they actually are divine or demonic miracles. There is a clear tension available to the film in pitting skeptical scientists against issues of faith, but the screenplay folds almost as soon as it begins.

That dovetails into the weirdest element of the film, which is an oddly evangelistic tone that permeates the horror and weakens the entire story. Horror works when it is inexplicable and terrifying. The Reaping ultimately seems to be pitching for a belief in a Christian God to defend oneself against Satan. By being so specific it ruins the uncertainty completely, and for a viewer tired of Christian proselytizing it actually irritates a little bit.

The film also ends in a large-scale, visual effects-oriented fashion, which is another quick kiss of death to horror and tension. Nobody is afraid of a massive computer-generated effect. The best horror is intimate, and small, and difficult to perceive.

This is all a tremendous shame, because as noted earlier the rest of the film actually does bring a lot of quality to the film. Hilary Swank delivers a very strong performance as a woman who has lost her faith, only to be violently challenged to find it again. She begins the film at least as a smart, analytical and bold scientific investigator. Idris Elba and David Morrissey are both effective in supporting roles. Director Stephen Hopkins – who has directed much better films than this including The Ghost and the Darkness and Under Suspicion – brings out some nice performances and staging throughout. It is all servicing a terrible screenplay, so in the final analysis all of the acting, direction and production values are little more than lipstick on a pig. ‘You can’t polish a turd,’ states one famous Hollywood maxim. ‘But you can roll it in glitter,’ states another.