Per the British Film Institute database, this is the second in an "unofficial trilogy" by Launder and Gilliat, along with Millions Like Us (1943) and Waterloo Road (1945).

During the 1940 Battle of France, Rosemary Brown (Patricia Roc), an English novice nun, is apprehended by French soldiers who have mistaken her for a fifth columnist.

She is sentenced to face a firing squad, but the Germans arrive and she is sent (without her habit, which is being cleaned) to an internment camp in a grand hotel at the spa town of Marneville.

At the camp, they meet Maud (Renée Houston), Margaret (Anne Crawford), Nellie (Dulcie Gray), Mrs Burtshaw (Thora Hird) and Teresa King (Betty Jardine).

Pilot Officer Jimmy Moore (James McKechnie), Sergeant Alec Harvey (Reginald Purdell) and Dave Kennedy (Robert Arden) seek refuge in the hotel.

[4] Phyllis Calvert said she was offered the part of the nun who falls in love with a pilot, but turned it down and Patricia Roc played it instead.

Calvert played Freda Thompson, even though she felt Launder and Gilliat "didn't like me turning down a part they had written for me, which I can understand".

[6] Perhaps because of the success of Three Came Home, the film was released in the USA in 1951 in a severely cut version under the title of House of 1,000 Women.