- Lord Robert St. Simon – Holmes's client, a nobleman whose wife has disappeared about ten minutes after their wedding.
- Hatty Doran – The missing wife, and the daughter of an American millionaire.
- Flora Miller – A dancer with whom St. Simon had an affair before marrying Doran.
- Aloysius Doran – Hatty's father.
- Francis Hay Moulton – Doran's first love, long presumed dead, who turns up again the morning of her wedding to St. Simon.
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