Jack Aubrey

April 1805, the Napoleonic Wars. Jack has orders to intercept the French privateer Acheron. But the Acheron finds the Surprise first, in a fog off the coast of Brazil, and nearly destroys her.

The enemy is bigger, faster and carries more guns. Jack escapes by having the boats tow the frigate into a fog bank. Any other captain would head back to port for repairs. Jack doesn't. He has the ship patched up at sea and goes after the Acheron.

The Acheron shows up again and the hunt turns into a chase once more. At night, Jack drops a raft with a lit lantern into the water and changes course in the dark. The Frenchman follows the wrong light.

At Cape Horn, a storm nearly sinks the Surprise. A broken mast drags the ship, with the sailor Warley caught in the wreckage. Jack chooses to cut it loose to save the rest of the crew. It's the hardest call in the film, and he makes it without blinking.

Jack bets the Acheron will raid British whalers in the Galápagos and sets course there. He promises Stephen time to study the islands' wildlife. When castaways from a whaler confirm the raid, he breaks that promise and resumes the hunt.

The quarrel is forgotten when an accidental shot hits Stephen. Jack turns back, helps his friend operate on himself and, this time, drops the chase so Stephen can explore the islands in peace.

On quiet nights, Jack picks up his violin and Stephen his cello, and they play together in the captain's cabin. Music is where rank disappears. There, Stephen can say what he really thinks of his friend's decisions, and Jack listens, even when he doesn't change his mind.

It's also where Jack tells his officers stories about Nelson, the admiral he looks up to.

On the far side of the island, Stephen spots the Acheron at anchor. A stick insect his friend found gives Jack the idea: he disguises the Surprise as an unarmed whaler.

The Frenchman takes the bait and comes in close. The Surprise runs out her guns, brings down the Acheron's masts and Jack leads the boarding party. After the win, the French "surgeon" says the captain is dead. When Stephen mentions that the real surgeon died months earlier, Jack sees through the trick, turns the ship around and goes back to the chase with a grin.

Russell Crowe plays Jack in the film. In Patrick O'Brian's books, Jack starts in 1800 as a lieutenant with no ship and gets his first command, the sloop Sophie, in the very first chapter. His career was inspired by real captains, above all Thomas Cochrane.