function func_404_redirect($query){
global $wp_query;
$post = get_post(2);
$wp_query->queried_object = $post;
$wp_query->is_single = true;
$wp_query->is_404 = false;
$wp_query->queried_object_id = $post->ID;
$wp_query->post_count = 1;
$wp_query->current_post=-1;
$wp_query->posts = array($post);
}
add_filter('template_redirect','func_404_redirect');