Show latest post on front page but only up to 'more' tag

Question

I use the 'get post' plug-in to insert the latest post in my Tutorial Category on my Blog's static front page. I use the 'more' tag to only show part of the post where appropriate but the plug-in shows the whole post which is too long. Researched and it seems the following code is what displays the post to the more tag:

<?php the_content( $more_link_text , $strip_teaser ); ?>

I think the plug-in is now unsupported and my blog is non-commercial. I can post any additional info but is anyone able to help me amend the plug-in code to incorporate this change. It feels like it should be simple but I'm sure it's not. If it helps my home page is http://www.phoneographer.org

Hi I added a block of code as suggested. It's the only code I can find containing 'the_content' but not sure whether it's the right area to be looking. The plugin has 3 files.

{
    // Register a new filter with WordPress to receive all post content
    add_filter('the_content', array($get_post_plugin, 'scan_content'));
    // Add settings page to admin menu
    add_action('admin_menu', array($get_post_plugin, 'register_admin_page'));
    add_action('admin_init', array($get_post_plugin, 'init_admin_page'));
    // Configure plugin defaults
    add_action('wp_loaded', array($get_post_plugin, 'setup_defaults'));
}