The Adventure of the Lion's Mane

"The Adventure of the Lion's Mane" (1926), one of the 56 Sherlock Holmes short stories written by British author Sir Arthur Conan Doyle, is one of 12 stories in the cycle collected as The Case-Book of Sherlock Holmes. It is notable for being narrated by Holmes himself, instead of by Dr. Watson (who does not appear in the story).
Holmes is enjoying his retirement in Sussex when one day at the beach, he meets his friend Harold Stackhurst, the headmaster of a nearby preparatory school called The Gables. No sooner have they met than Stackhurst's science teacher, Fitzroy McPherson, staggers up to them, clearly in agony and wearing only an overcoat and trousers. He collapses, manages to say something about a "lion's mane", and then succumbs. He is observed to have red welts all over his back, possibly administered by a flexible weapon of some kind, for the marks curve over his shoulder and round his ribs.
Moments later, Ian Murdoch, a mathematics teacher at The Gables, comes up behind them. He has not seen the attack, and has only just arrived at the beach from the school. Holmes sees a couple of people far up the beach, but thinks they are much too far away to have had anything to do with McPherson's death. Likewise, the few fishing boats off the beach are too far out...
Famous works of the author Arthur Conan Doyle: A Study in Scarlet, The Sign of the Four, The Adventures of Sherlock Holmes, The Memoirs of Sherlock Holmes, The Hound of the Baskervilles, The Return of Sherlock Holmes, The Valley of Fear, His Last Bow, The Case-Book of Sherlock Holmes, Stories of Sherlock Holmes, The Lost World.