When a friendless old widow dies in the seaside town of Crythin, a young solicitor is sent by his firm to settle the estate. The lawyer finds the townspeople reluctant to talk about or go near the woman's dreary home and no one will explain or even acknowledge the menacing woman in black he keeps seeing.
Young graduate student Jane Chase becomes the new assistant to an eccentric zoology professor at the remote home he shares with two brilliant chimpanzees and an elderly orangutan butler named Link. But when one of the chimps is found dead and the professor mysteriously disappears, Link becomes dangerously aggressive towards Jane. Now, the time for “monkey business” is over and the true terror is about to begin.
A man dies suddenly of a mysterious fever, and Holmes suspects murder.