Star Trek V: The Final Frontier

The clearest skip in the franchise's film run. William Shatner directed it, having negotiated the opportunity after Nimoy directed the previous two, and the result is the only Star Trek film that is widely held to be bad rather than merely minor.

The pitch was not stupid. A charismatic Vulcan who has rejected logic in favour of feeling hijacks a starship to reach a planet at the centre of the galaxy where he believes God is waiting, and the question of what the crew would find there is a reasonable one for this franchise to ask. The answer the film arrives at is thin, and the production could not afford to stage it: a strike had disrupted the script, the budget was cut, and the effects house that had done the previous films was unavailable, which is why the climax looks the way it does.

What survives are the character scenes. The campfire sequence at the start and end, with three old men arguing about marshmallows and mortality, is genuinely lovely and is the only part anybody defends. The scene where the villain offers to take away each character's deepest pain and Kirk refuses on the grounds that his pain is what made him is the film's one real idea.

Everything between those is broad comedy that does not land, a rock-climbing opening, and a Klingon subplot going nowhere. Nothing later depends on it.