The year is 1943. A group of British soldiers has arrived at a Japanese concentration camp located somewhere in Burma. These soldiers are led by Lieutenant Colonel Nicholson (Alec Guinness), the perfect model of a rule-following military man. Overseeing this P.O.W. camp is General Saito (Sessue Hayakawa), who insists that, in a violation of the Genova Convention, all prisoners, including lieutenants, will be put to work on constructing a bridge. Nicholson initially refuses and is put inside a cramped box as punishment for his efforts. Eventually, Nichols relents and begins to throw himself into making this the best bridge you've ever seen. Meanwhile, long-time prisoner Lieutenant Commander Shears (William Holden) has managed to escape the camp, though he'll soon be returning when he's hired to lead an expedition to blow this new bridge up.
Filmed in the CinemaScope format, The Bridge on the River Kwai is a movie all about expansive imagery. The daunting nature of the P.O.W. camp is effectively conveyed just in how Lean uses these massive shots. Every inch of this place and its surrounding jungle is caught in a single image. The viewer never loses sight of how there's danger at every turn for these captured men. Meanwhile, the ambition of the bridge is similarly reflected in extended wide shots that make the scale of this project obvious. Lean loves grandiose imagery, but one reason it never comes at the expense of depth is how there's always a larger character-centric point behind it. The tools at his disposal are being used for a purpose and not for showing off.
Just look at how wider shots are used in early scenes to show how Nicholson can gather the rapt attention of all his men so easily. These shots show Nicholson speaking while a dozen men (plus the jaded Shears) linger around him, listening to his every word. You'd still get the engaging performance from Guinness in a more cramped shot. But by pulling the camera out, one can immediately tell how this guy is a natural-born leader. This effortlessly and stylishly establishes who Nichsolon is early on, which makes the places he's taken to throughout the screenplay by Carl Foreman and Michael Wilson all the more interesting.
At first, Foreman and Wilson's script is content to undercut Nicholson's initially established personality by emphasizing his vulnerability. Nicholson's time spent in a box leaves him ratty, dirty, and riddled with bruises. To see this guy so obviously worn down by the world is a startling sight. But then things get even more intriguing once Nicholson throws himself into building this bridge. Cut off from the rest of the world after spending decades in the trenches, this railway is now what Nicholson lives for. The character constantly goes down incredibly compelling directions, all brought to life with such vivid believability by Guinness.
In a secondary storyline, Shears leads a group of men back to the place he was held prisoner. This plot includes its own share of enjoyable surprises, including a brilliantly-handled reveal regarding the true identity of Shears. Both plotlines converge in a masterful climax where Shears and his men try to blow up the bridge only for Nicholson to get wise to the plan at the last minute. This whole sequence works as a masterclass in how to execute suspense, particularly as Nicholson gets closer and closer to figuring out what's going on. Lean refusing to cut away from the brutality of this moment (not every character you like gets out of here alive) makes both the suspense and moral complexity of this finale all the more engrossing. Though it's a climax that ends with a big o'l bang, this ending to The Bridge on the River Kwai epitomizes how well Lean could juggle spectacle with intimate stakes.