vetala

I figured it out.

In single_book.php I changed this:

<div class="entry-content clear">
        <?php $title = get_post_meta( 'content_title' ); if( ! $title ) $title = __( 'About This Book', 'totally-booked' ); ?>
        <h3 class="content-title"><?php esc_html_e( $title ); ?></h3>
        <?php the_content(); ?>
        <?php echo tb_get_entry_meta(); ?>
</div>

To this:

<div class="entry-content clear">
        <?php $title = get_post_meta( 'content_title' ); if( ! $title ) $title = __( 'About This Book', 'totally-booked' ); ?>
        <h3 class="content-title"><?php esc_html_e( $title ); ?></h3>
        <?php the_content(); ?>
        <?php echo tb_get_entry_meta(); ?>
		<div class="clear"></div>
</div>

No more plugin content showing up in the footer:

http://www.vetala.me/wp/books/hitchhikers-guide-to-the-galaxy/

Hope this helps someone at some point.