Ronnie Winslow (Neil North) has been kicked out of naval school for the theft of a postal order, but Ronnie vehemently denies stealing it. His father, Arthur (Cedric Hardwicke), and his suffragete sister, Catherine (Margaret Leighton), will move heaven and earth to prove Ronnie's innocence. They soon receive the help of Sir Robert Morton (Robert Donat), the talented barrister who, although eccentric, proves to truly care about this serious miscarriage of "right".
The Winslow Boy shows the following tropes:
- Arc Words:
- "Let Right Be Done."
- Belligerent Sexual Tension: Between Sir Robert and Catherine.
- Courtroom Antics: Sir Robert Morton's antics in the House of Commons involve throwing his books on the floor and leaving in a huff without speaking. He then continually interrupts the Attorney General's cross-examination of Ronnie and suggests he might have to ask for an adjournment (although the last one wasn't a trick).Sir Robert:The House of Commons is a peculiarly trying place you know - far too little ventilation and far too much hot air.
- Deadpan Snarker: Sir Robert and Catherine have their moments.
- Determinator: The Winslows, especially Mr. Winslow and Catherine.
- Jerk with a Heart of Gold: Sir Robert feigns coldness but actually cares about the Winslows. So much so, that he gives up an prestigious opportunity to fight on their behalf.
- Judicial Wig: Barristers in an English high court must wear wigs.
- Kangaroo Court: The Naval inquiry into the theft was more or less this.Sir Robert: And, at this inquiry, did Ronald Winslow have anyone to defend him?Captain Flower: Oh, that was different.Sir Robert: Oh, yes, of course it was different. You were a man of 22 [reference the Flowers inquiry of over 20 years ago] but he was a child of 13. Thank you captain, that is all.
- Miscarriage of Justice: The whole issue of the film.
- Straw Feminist: Averted: Catherine strongly believes in the rights of women, but as she puts it, shes no militant.
- Wham Line:Sir Robert: Still pursuing your feminist activities, Miss Winslow?Catherine: Oh yes.Sir Robert: Pity. It's a lost cause.Catherine: How little you know women, Sir Robert. Goodbye. I doubt if we should meet again.Sir Robert: Oh, do you really think so? How little you know men, Miss Winslow.
- Will They or Won't They?: As the last zinger of the film can attest to, it looks like a will they situation.