Read The Sign of the Four in Englishwith every sentence explained

The Sign of the Four by Arthur Conan Doyle was first published in 1890. In Passage you read the full text in the original English, marked intermediate and filed under mystery and crime and thriller and suspense.

"Which is it today?" I asked. "Morphine or cocaine?"

For Sherlock Holmes, the dullness of daily life is a burden only the most complex cases, or a seven-per-cent solution, can relieve. But his boredom is shattered when Mary Morstan arrives at 221B Baker Street with a baffling mystery. Years after her father vanished, an anonymous sender began posting her a single rare, lustrous pearl every year. Now a mysterious letter has summoned her to a meeting, and she wants Holmes and Watson at her side.

What begins as a search for a missing father spirals into a deadly affair of stolen Indian treasure, a secret pact sworn by four men, and a relentless enemy who leaves very strange footprints behind. From the foggy streets of London to the dark waters of the Thames, The Sign of the Four is Arthur Conan Doyle's second Holmes novel: fast, atmospheric and full of the famous "Science of Deduction".

Passage sets the book as a quiet, paginated reader in English. Read at your own pace, and when a sentence stops you, tap it. You get:

• a natural translation of that exact sentence,
• a short note on the grammar, in plain words,
• the key words, which you can save with the sentence they came from,
• all of it in English, Spanish, French, German, Italian, Turkish or Portuguese, whichever you read best.

It's marked intermediate: comfortable once everyday English feels familiar, with the harder sentences one tap away. The words you save come back later in short review games, so the book keeps teaching after you close it.