Sherlock Holmes is facing his worst enemy: declining crowds at the box office.
Robert Downey Jr.'s sequel "Sherlock Holmes: A Game of Shadows" debuted on top with a $40 million weekend, off 36 percent from the first installment's $62.3 million debut two years ago.
The first movie opened over Christmas weekend, one of the busiest times for movie theaters. Distributor Warner Bros. predicts the "Holmes" sequel will make up the lost ground over the holidays.
But overall business was down again, a sign of the times as Hollywood struggles to interest audiences in its big year-end releases.
"Alvin and the Chipmunks: Chipwrecked" did even worse than "Holmes." "Chipwrecked" opened at No. 2 with $23.5 million, about half the business the first two "Chipmunks" movies did on their debut weekends.