Twenty years after the murder of Zira and Cornelius, their child Caesar (Roddy McDowall), rejoins the world from hiding in a circus. He finds a society where apes are kept as pets performing menial tasks, and often mistreated. When his guardian Armando (Ricardo Montalban) is killed, Caesar organises a revolution.
Acceptance of this fourth Apes film will rely greatly on your swallowing the presentation of its world in microcosm – a solution often employed in sci-fi to circumvent the hassle of the 'big ideas vs tiny budget' conundrum. If you don't, you'll sit incredulous as to how a pack of simians rioting on what looks like a Thamesmead housing estate equates to world domination.
But even for more forgiving fans of the story so far, Conquest feels a bit like going through the motions. As we follow Caesar on his journey from secretly intelligent but peaceful young ape to angry revolutionary, slavery and fascism analogies are drawn, and a few key moments hitherto alluded to in Ape law are checked off.
It's also the end of the series' strongest drawcard – the downbeat endings. When the chance for another memorable catastrophe is presented and not taken, it's a cue for all concerned to hang up the simian suits. Sadly, this went unheeded.
Wringing the last drops out of the idea, it strains to stay on-side, but it remains true enough to the spirit of the series to get it over the line.