The Last Airbender had a good beginning with a solid $70.5 million from its Thursday opening through Monday. The promising initial figures show that the core audience of the film, which cost Paramount Pictures about $150 million to make, was not repelled by pouring negative reviews.

However, reports say Paramount has reasons to worry that its only big-budget event movie of the summer may disappear from theatres swiftly. Except on Sunday and Monday, ticket sales were falling every day that the film was in theatres. Moviegoers gave it an average grade of C, according to market research firm CinemaScore. The rating indicates the audiences are not saying good things to friends and relatives about the movie.

The Last Airbender is based on a Nickelodeon cartoon that is popular with boys. It drew an audience that was 55 percent male, and 55 percent younger than 25.

M. Night Shyamalan directed the action-adventure picture, which played in 3-D at a little more than half its theatres.

The film has yet to open internationally, where it may accomplish better figures given its extensive special effects and multicultural cast.