Joan Webster (Wendy Hiller) is a young middle class Englishwoman with an ambitious, independent spirit. She knows where she's going, or at least she thinks she does. She travels from her home in Manchester to the Hebrides to marry Sir Robert Bellinger, a very wealthy, much older industrialist, on the (fictitious) Isle of Kiloran.
When bad weather postpones the final leg of her journey—a boat trip to Kiloran—she is forced to wait it out on the Isle of Mull, among a community of people whose values are quite different from hers. There she meets Torquil MacNeil (Roger Livesey), a naval officer trying to go home to Kiloran for some shore leave. They are sheltered for the night in the nearby home of Torquil's friend, Catriona Potts (Pamela Brown).
The next day, on their way to catch a bus into town, they come upon the ruins of Moy Castle. Joan wants to take a look inside, but Torquil refuses to go in. When she reminds him that the terrible curse only applies to the Laird of Kiloran, Torquil introduces himself: he is the laird, and Bellinger has only leased his island. As the bad weather worsens into a full-scale gale, Torquil takes advantage of the delay to woo Joan, who becomes increasingly torn between her ambition and her growing attraction to him.
Desperate to salvage her carefully laid plans, Joan tries to persuade Ruairidh Mhór (Finlay Currie) to take her across to the island immediately, but the experienced sailor knows conditions are far too dangerous. Joan manages to bribe young Kenny (Murdo Morrison) into attempting it by offering him enough money to buy a half share in Ruairidh's boat and marry Ruairidh's daughter Bridie (Margot Fitzsimons). Torquil learns of the scheme and tries to talk Joan out of it, but she proves adamant and they have a blazing row. After Joan has gone down to the boat, Catriona tells MacNeil that Joan is actually running away from him. Armed with this knowledge, he races to the quayside and invites himself aboard. The boat's engine gets flooded and they are caught in the Corryvreckan whirlpool, but Torquil is able to restart the motor just in time and they return safely to Mull.
At last, the weather clears. Joan asks Torquil for a parting kiss before they go their separate ways. Torquil enters Moy Castle, and the curse takes effect almost immediately. A narrator relates that, centuries earlier, Torquil's ancestor had stormed the castle to capture his unfaithful wife and her lover. He had them bound together and cast into a water-filled dungeon with only a small stone to stand upon. When their strength gave out, they dragged each other into the water, but not before she placed a curse on the Lairds of Kiloran. Any who dared to step over the threshold would be chained to a woman to the end of his days. From the battlements, Torquil sees Joan with three pipers marching resolutely toward him. They embrace.Wendy Hiller as Joan Webster
Roger Livesey as Torquil MacNeil
Pamela Brown as Catriona
Finlay Currie as Ruairidh Mhór
George Carney as Mr. Webster
Nancy Price as Mrs. Crozier
Catherine Lacey as Mrs. Robinson, a chatterbox friend of Bellinger's who is on holiday in the area
Jean Cadell as the Postmistress
John Laurie as John Campbell, son of the couple whose diamond anniversary céilidh Torquil and Joan attend
Valentine Dyall as Mr. Robinson, a business associate of Bellinger's and Mrs. Robinson's husband
Norman Shelley as Sir Robert Bellinger (voice)
Margot Fitzsimons as Bridie
Murdo Morrison as Kenny
Captain C.W.R. Knight as Colonel Barnstaple, falconer and friend of Torquil and Catriona
Walter Hudd as Hunter, one of Bellinger's employees
Mr. Ramshaw as Torquil, the Eagle
John Rae as Old Shepherd
Anthony Eustrel as Hooper
Herbert Lomas as Mr. Campbell
Graham Moffatt as R.A.F. Sergeant
Cast notes:Petula Clark played Cheril, the precocious daughter of the Robinsons, in her fourth film appearance.
Making their third appearance in I Know Where I'm Going! were director Michael Powell's golden cocker spaniels Erik and Spangle, who had previously appeared in Contraband (1940) and The Life and Death of Colonel Blimp (1943), and went on to be seen in Powell and Pressburger's A Matter of Life and Death, also known as Stairway to Heaven (1946).
The original story and the whole screenplay were written in less than a week. Pressburger said it just flowed naturally.
The film was shot in black and white while Powell and Pressburger were waiting for a Technicolor camera to begin making their next film, A Matter of Life and Death (Technicolor cameras and technical specialists were mostly in Hollywood during WWII). It was the second and last collaboration between the co-directors and cinematographer Erwin Hillier (who shot the entire film without using a light meter).
From various topographical references and a map briefly shown in the film, it is clear that the Isle of Kiloran is based on Colonsay. The name Kiloran was borrowed from one of Colonsay's bays, Kiloran Bay. The heroine of the film is trying to get to Kiloran (Colonsay), but nobody ever gets there. No footage was shot on Colonsay.
One of the most complex scenes is the small boat battling through the Corryvreckan whirlpool. This was a combination of footage shot at Corryvreckan between the Hebridean islands of Scarba and Jura and the Gray Dogs (Bealach a'Choin Ghlais) between Scarba and Lunga.There are some long distance shots looking down over the area, shot from one of the islands.
There are some middle distance and close-up shots that were made from a small boat with a hand-held camera.
There were some model shots, done in the tank at the studio. These had gelatin added to the water so that it would hold its shape better and would look better when scaled up. Usually the way that waves break and the size of water drops is a give-away for model shots done in a tank.
Then there were also the close-up shots of the people in the boat. These were all done in the studio, with a boat on gimbals being rocked in all directions by some hefty studio hands while other studio hands threw buckets of water at them. These were filmed with the shots made from the boat with the hand-held camera projected behind them.
Even then, there was further trickery where they joined together some of the long and middle distance shots with those made in the tank in a single frame.
Despite the fact that much of the film was shot in the Hebrides, Roger Livesey was not able to travel to Scotland, as he was performing in a West End play, The Banbury Nose by Peter Ustinov at the time of filming. Thus, all of his scenes were shot in the studio at Denham and a double was used in all of his scenes shot in Scotland. These shots were then mixed so that the same scene would often have a middle distance shot of the double and then a closeup of Livesey, or a shot of the double's back followed by a shot showing Livesey's face.
John Laurie was the choreographer and arranger for the cèilidh sequences. The puirt à beul "Macaphee" was performed by Boyd Steven, Maxwell Kennedy and Jean Houston of the Glasgow Orpheus Choir.
Other music heard in the film is either traditional Scottish and Irish songs or original music composed for the film by Allan Gray.On the Isle of Mull
Carsaig Bay: Carsaig Pier and boathouses, Carsaig House (Erraig), telephone box next to the waterfall.
Moy Castle - Castle of Moy
Duart Castle - Castle of Sorne
Torosay Castle - Achnacroish
Gulf of Corryvreckan - the whirlpool
The film has received accolades from many critics:"I've never seen a picture which smelled of the wind and rain in quite this way nor one which so beautifully exploited the kind of scenery people actually live with, rather than the kind which is commercialised as a show place." – Raymond Chandler, Letters.
"The cast makes the best possible use of some natural, unforced dialogue, and there is some glorious outdoor photography." – The Times, 14 November 1945
"[It] has interest and integrity. It deserves to have successors." – The Guardian, 16 November 1945
"I reached the point of thinking there were no more masterpieces to discover, until I saw I Know Where I'm Going!" – Martin Scorsese
The film critic Barry Norman included it among his 100 greatest films of all time.
The film critic Molly Haskell included it among her 10 greatest films of all time, in the 2012 Sight & Sound poll.